diff --git a/cmd/xlabuilder_codegen/go_ops.go b/cmd/xlabuilder_codegen/go_ops.go
index e78dba3..215c058 100644
--- a/cmd/xlabuilder_codegen/go_ops.go
+++ b/cmd/xlabuilder_codegen/go_ops.go
@@ -43,6 +43,9 @@ func {{.Name}}(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of {{.Name}}(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp({{.Name}}Op, x0, x1)
 	err := builder.addOp(y)
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 7d3174f..69d7533 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -5,6 +5,7 @@
 * Use `github.com/dmarkham/enumer` instead of the usual `stringer` for dtypes.
 * Fixed double free of C.XlaOp pointers for Identity ops.
 * Added `DynamicSlice` and `DynamicSliceUpdate`.
+* Added check for matching DTypes for the common ops taking 2 operands.
 
 # v0.2.0 GoMLX integration fixes -- GoMLX more extensive tests caught several small issues in Gopjrt.
 
diff --git a/xlabuilder/gen_simple_ops.go b/xlabuilder/gen_simple_ops.go
index 6f61777..21e4c56 100644
--- a/xlabuilder/gen_simple_ops.go
+++ b/xlabuilder/gen_simple_ops.go
@@ -265,6 +265,9 @@ func Add(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Add(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(AddOp, x0, x1)
 	err := builder.addOp(y)
@@ -281,6 +284,9 @@ func Mul(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Mul(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(MulOp, x0, x1)
 	err := builder.addOp(y)
@@ -297,6 +303,9 @@ func Sub(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Sub(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(SubOp, x0, x1)
 	err := builder.addOp(y)
@@ -313,6 +322,9 @@ func Div(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Div(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(DivOp, x0, x1)
 	err := builder.addOp(y)
@@ -329,6 +341,9 @@ func Rem(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Rem(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(RemOp, x0, x1)
 	err := builder.addOp(y)
@@ -344,6 +359,9 @@ func And(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of And(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(AndOp, x0, x1)
 	err := builder.addOp(y)
@@ -359,6 +377,9 @@ func Or(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Or(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(OrOp, x0, x1)
 	err := builder.addOp(y)
@@ -374,6 +395,9 @@ func Xor(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Xor(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(XorOp, x0, x1)
 	err := builder.addOp(y)
@@ -402,6 +426,9 @@ func Dot(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Dot(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(DotOp, x0, x1)
 	err := builder.addOp(y)
@@ -417,6 +444,9 @@ func Min(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Min(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(MinOp, x0, x1)
 	err := builder.addOp(y)
@@ -432,6 +462,9 @@ func Max(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Max(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(MaxOp, x0, x1)
 	err := builder.addOp(y)
@@ -447,6 +480,9 @@ func Pow(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Pow(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(PowOp, x0, x1)
 	err := builder.addOp(y)
@@ -467,6 +503,9 @@ func Complex(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Complex(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(ComplexOp, x0, x1)
 	err := builder.addOp(y)
@@ -482,6 +521,9 @@ func Equal(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of Equal(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(EqualOp, x0, x1)
 	err := builder.addOp(y)
@@ -497,6 +539,9 @@ func NotEqual(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of NotEqual(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(NotEqualOp, x0, x1)
 	err := builder.addOp(y)
@@ -512,6 +557,9 @@ func GreaterOrEqual(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of GreaterOrEqual(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(GreaterOrEqualOp, x0, x1)
 	err := builder.addOp(y)
@@ -527,6 +575,9 @@ func GreaterThan(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of GreaterThan(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(GreaterThanOp, x0, x1)
 	err := builder.addOp(y)
@@ -542,6 +593,9 @@ func LessOrEqual(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of LessOrEqual(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(LessOrEqualOp, x0, x1)
 	err := builder.addOp(y)
@@ -557,6 +611,9 @@ func LessThan(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of LessThan(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(LessThanOp, x0, x1)
 	err := builder.addOp(y)
@@ -576,6 +633,9 @@ func EqualTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of EqualTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(EqualTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
@@ -595,6 +655,9 @@ func NotEqualTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of NotEqualTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(NotEqualTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
@@ -614,6 +677,9 @@ func GreaterOrEqualTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of GreaterOrEqualTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(GreaterOrEqualTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
@@ -633,6 +699,9 @@ func GreaterThanTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of GreaterThanTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(GreaterThanTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
@@ -652,6 +721,9 @@ func LessOrEqualTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of LessOrEqualTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(LessOrEqualTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
@@ -671,6 +743,9 @@ func LessThanTotalOrder(x0, x1 *Op) (*Op, error) {
 	if x0.builder != x1.builder {
 		return nil, errors.New("arguments of LessThanTotalOrder(x0, x1) come from different XlaBuilder objects (or nil)")
 	}
+	if x0.Shape.DType != x1.Shape.DType {
+		return nil, errors.Errorf("dtype of first (%s) and second (%s) operands don't match", x0.Shape.DType, x1.Shape.DType)
+	}
 	builder := x0.builder
 	y := newOp(LessThanTotalOrderOp, x0, x1)
 	err := builder.addOp(y)
diff --git a/xlabuilder/special_ops.go b/xlabuilder/special_ops.go
index 7e1ef07..63cc215 100644
--- a/xlabuilder/special_ops.go
+++ b/xlabuilder/special_ops.go
@@ -203,6 +203,9 @@ func Where(condition, onTrue, onFalse *Op) (*Op, error) {
 		return nil, errors.New("trying to access XlaBuilder that is nil or already destroyed")
 	}
 	builder := condition.builder
+	if onTrue.Shape.DType != onFalse.Shape.DType {
+		return nil, errors.Errorf("dtype of onTrue (%s) and onFalse (%s) don't match", onTrue.Shape.DType, onFalse.Shape.DType)
+	}
 	op := newOp(WhereOp, condition, onTrue, onFalse)
 	err := builder.addOp(op)
 	if err != nil {
@@ -386,6 +389,13 @@ func Concatenate(axis int, operands ...*Op) (*Op, error) {
 		// Trivial solution.
 		return operands[0], nil
 	}
+	dtype := operands[0].Shape.DType
+	for ii, op := range operands {
+		if op.Shape.DType != dtype {
+			return nil, errors.Errorf("Concatenate operand 0 has dtype %s, by operand %d has dtype %s: dtypes must match",
+				dtype, ii, op.Shape.DType)
+		}
+	}
 	builder := operands[0].builder
 	op := newOp(ConcatenateOp, operands...)
 	op.IntArg = axis
@@ -508,6 +518,9 @@ func Pad(x, fillValue *Op, axesConfig ...PadAxis) (*Op, error) {
 	if rank == 0 {
 		return nil, errors.New("cannot use Pad() with scalar values")
 	}
+	if x.Shape.DType != fillValue.Shape.DType {
+		return nil, errors.Errorf("operand and fillValue dtypes (%s and %s) don't match for Pad()", x.Shape.DType, fillValue.Shape.DType)
+	}
 	op := newOp(PadOp, x, fillValue)
 	op.IntsArg = make([]int, 0, 3*rank)
 	for axis := 0; axis < rank; axis++ {
@@ -1331,6 +1344,9 @@ func DecodeDynamicSlice(op *Op) (operand *Op, startIndices []*Op, sliceDims []in
 // See description in https://openxla.org/xla/operation_semantics#dynamicupdateslice
 func DynamicUpdateSlice(operand, update *Op, startIndices []*Op) (*Op, error) {
 	builder := operand.builder
+	if operand.Shape.DType != update.Shape.DType {
+		return nil, errors.Errorf("operand and update dtypes (%s and %s) don't match for DynamicUpdateSlice", operand.Shape.DType, update.Shape.DType)
+	}
 	allOps := append([]*Op{operand, update}, startIndices...)
 	op := newOp(DynamicUpdateSliceOp, allOps...)
 	err := builder.addOp(op)