diff --git a/internal/gengapic/custom_operation.go b/internal/gengapic/custom_operation.go
index 51686a60..f4af5804 100644
--- a/internal/gengapic/custom_operation.go
+++ b/internal/gengapic/custom_operation.go
@@ -192,8 +192,10 @@ func (g *generator) customOperationType() error {
 	p("}")
 	p("")
 	g.imports[pbinfo.ImportSpec{Path: "context"}] = true
-	g.imports[pbinfo.ImportSpec{Name: "gax", Path: "github.com/googleapis/gax-go/v2"}] = true
 	g.imports[pbinfo.ImportSpec{Path: "time"}] = true
+	g.imports[pbinfo.ImportSpec{Name: "gax", Path: "github.com/googleapis/gax-go/v2"}] = true
+	g.imports[pbinfo.ImportSpec{Path: "github.com/googleapis/gax-go/v2/apierror"}] = true
+	g.imports[pbinfo.ImportSpec{Path: "google.golang.org/api/googleapi"}] = true
 
 	for _, handle := range op.handles {
 		pollingParams := op.pollingParams[handle]
@@ -204,6 +206,17 @@ func (g *generator) customOperationType() error {
 		poll := operationPollingMethod(handle)
 		pollReq := g.descInfo.Type[poll.GetInputType()].(*descriptor.DescriptorProto)
 		pollNameField := operationResponseField(pollReq, opNameField.GetName())
+		// Look up the fields for error code and error message.
+		errorCodeField := operationField(op.message, extendedops.OperationResponseMapping_ERROR_CODE)
+		if errorCodeField == nil {
+			return fmt.Errorf("field %s not found in %T", extendedops.OperationResponseMapping_ERROR_CODE, op)
+		}
+		errorCode := snakeToCamel(errorCodeField.GetName())
+		errorMessageField := operationField(op.message, extendedops.OperationResponseMapping_ERROR_MESSAGE)
+		if errorMessageField == nil {
+			return fmt.Errorf("field %s not found in %T", extendedops.OperationResponseMapping_ERROR_MESSAGE, op)
+		}
+		errorMessage := snakeToCamel(errorMessageField.GetName())
 
 		// type
 		p("// Implements the %s interface for %s.", handleInt, handle.GetName())
@@ -229,6 +242,19 @@ func (g *generator) customOperationType() error {
 		p("    return err")
 		p("  }")
 		p("  h.proto = resp")
+		p("  if resp.%[1]s != nil && (resp.Get%[1]s() < 200 || resp.Get%[1]s() > 299) {", errorCode)
+		p("  	aErr := &googleapi.Error{")
+		p("  		Code: int(resp.Get%s()),", errorCode)
+		if hasField(op.message, "error") {
+			g.imports[pbinfo.ImportSpec{Path: "fmt"}] = true
+			p(`  		Message: fmt.Sprintf("%%s: %%v", resp.Get%s(), resp.GetError()),`, errorMessage)
+		} else {
+			p("  		Message: resp.Get%s(),", errorMessage)
+		}
+		p("  	}")
+		p("  	err, _ := apierror.FromError(aErr)")
+		p("  	return err")
+		p("  }")
 		p("  return nil")
 		p("}")
 		p("")
diff --git a/internal/gengapic/custom_operation_test.go b/internal/gengapic/custom_operation_test.go
index a030e5fe..c383cd49 100644
--- a/internal/gengapic/custom_operation_test.go
+++ b/internal/gengapic/custom_operation_test.go
@@ -121,6 +121,38 @@ func TestCustomOpInit(t *testing.T) {
 }
 
 func TestCustomOperationType(t *testing.T) {
+	errorType := &descriptor.DescriptorProto{
+		Name: proto.String("Error"),
+		Field: []*descriptor.FieldDescriptorProto{
+			{
+				Name:  proto.String("nested"),
+				Type:  typep(descriptor.FieldDescriptorProto_TYPE_STRING),
+				Label: labelp(descriptor.FieldDescriptorProto_LABEL_OPTIONAL),
+			},
+		},
+	}
+	errorField := &descriptor.FieldDescriptorProto{
+		Name:     proto.String("error"),
+		Type:     typep(descriptor.FieldDescriptorProto_TYPE_MESSAGE),
+		TypeName: proto.String("Error"),
+	}
+
+	errorCodeOpts := &descriptor.FieldOptions{}
+	proto.SetExtension(errorCodeOpts, extendedops.E_OperationField, extendedops.OperationResponseMapping_ERROR_CODE)
+	errorCodeField := &descriptor.FieldDescriptorProto{
+		Name:    proto.String("http_error_status_code"),
+		Type:    descriptor.FieldDescriptorProto_TYPE_STRING.Enum(),
+		Options: errorCodeOpts,
+	}
+
+	errorMessageOpts := &descriptor.FieldOptions{}
+	proto.SetExtension(errorMessageOpts, extendedops.E_OperationField, extendedops.OperationResponseMapping_ERROR_MESSAGE)
+	errorMessageField := &descriptor.FieldDescriptorProto{
+		Name:    proto.String("http_error_message"),
+		Type:    descriptor.FieldDescriptorProto_TYPE_STRING.Enum(),
+		Options: errorMessageOpts,
+	}
+
 	nameOpts := &descriptor.FieldOptions{}
 	proto.SetExtension(nameOpts, extendedops.E_OperationField, extendedops.OperationResponseMapping_NAME)
 	nameField := &descriptor.FieldDescriptorProto{
@@ -213,25 +245,31 @@ func TestCustomOperationType(t *testing.T) {
 			},
 			Type: map[string]pbinfo.ProtoType{
 				statusEnumField.GetTypeName():                 statusEnum,
+				".google.cloud.foo.v1.Error":                  errorType,
 				".google.cloud.foo.v1.GetFooOperationRequest": getInput,
 			},
 		},
 		imports: map[pbinfo.ImportSpec]bool{},
 	}
 	for _, tst := range []struct {
-		name string
-		st   *descriptor.FieldDescriptorProto
+		name       string
+		st         *descriptor.FieldDescriptorProto
+		errorField bool
 	}{
 		{
 			name: "enum",
 			st:   statusEnumField,
 		},
 		{
-			name: "bool",
-			st:   statusBoolField,
+			name:       "bool",
+			st:         statusBoolField,
+			errorField: true,
 		},
 	} {
-		op.Field = []*descriptor.FieldDescriptorProto{nameField, tst.st}
+		op.Field = []*descriptor.FieldDescriptorProto{errorCodeField, errorMessageField, nameField, tst.st}
+		if tst.errorField {
+			op.Field = append(op.Field, errorField)
+		}
 		err := g.customOperationType()
 		if err != nil {
 			t.Fatal(err)
diff --git a/internal/gengapic/helpers.go b/internal/gengapic/helpers.go
index 67b1d84c..0d5424db 100644
--- a/internal/gengapic/helpers.go
+++ b/internal/gengapic/helpers.go
@@ -110,6 +110,17 @@ func grpcClientField(reducedServName string) string {
 	return lowerFirst(reducedServName + "Client")
 }
 
+// hasField returns true if the target DescriptorProto has the given field,
+// otherwise it returns false.
+func hasField(m *descriptor.DescriptorProto, field string) bool {
+	for _, f := range m.GetField() {
+		if f.GetName() == field {
+			return true
+		}
+	}
+	return false
+}
+
 // hasMethod reports if the given service defines an RPC with the same name as
 // the given simple method name.
 func hasMethod(service *descriptor.ServiceDescriptorProto, method string) bool {
diff --git a/internal/gengapic/helpers_test.go b/internal/gengapic/helpers_test.go
index ab0bbc35..332b6d7c 100644
--- a/internal/gengapic/helpers_test.go
+++ b/internal/gengapic/helpers_test.go
@@ -144,6 +144,26 @@ func TestStrContains(t *testing.T) {
 	}
 }
 
+func TestHasField(t *testing.T) {
+	msg := &descriptor.DescriptorProto{
+		Field: []*descriptor.FieldDescriptorProto{
+			{Name: proto.String("foo")},
+			{Name: proto.String("bar")},
+		},
+	}
+	for _, tst := range []struct {
+		in   string
+		want bool
+	}{
+		{in: "foo", want: true},
+		{in: "baz"},
+	} {
+		if got := hasField(msg, tst.in); !cmp.Equal(got, tst.want) {
+			t.Errorf("TestHasField got %v want %v", got, tst.want)
+		}
+	}
+}
+
 func TestHasMethod(t *testing.T) {
 	serv := &descriptor.ServiceDescriptorProto{
 		Method: []*descriptor.MethodDescriptorProto{
diff --git a/internal/gengapic/testdata/custom_op_type_bool.want b/internal/gengapic/testdata/custom_op_type_bool.want
index 14c90252..18bc8ff8 100644
--- a/internal/gengapic/testdata/custom_op_type_bool.want
+++ b/internal/gengapic/testdata/custom_op_type_bool.want
@@ -61,6 +61,14 @@ func (h *fooOperationsHandle) Poll(ctx context.Context, opts ...gax.CallOption)
 		return err
 	}
 	h.proto = resp
+	if resp.HttpErrorStatusCode != nil && (resp.GetHttpErrorStatusCode() < 200 || resp.GetHttpErrorStatusCode() > 299) {
+		aErr := &googleapi.Error{
+			Code: int(resp.GetHttpErrorStatusCode()),
+			Message: fmt.Sprintf("%s: %v", resp.GetHttpErrorMessage(), resp.GetError()),
+		}
+		err, _ := apierror.FromError(aErr)
+		return err
+	}
 	return nil
 }
 
diff --git a/internal/gengapic/testdata/custom_op_type_enum.want b/internal/gengapic/testdata/custom_op_type_enum.want
index b747113a..3bb1e3a5 100644
--- a/internal/gengapic/testdata/custom_op_type_enum.want
+++ b/internal/gengapic/testdata/custom_op_type_enum.want
@@ -61,6 +61,14 @@ func (h *fooOperationsHandle) Poll(ctx context.Context, opts ...gax.CallOption)
 		return err
 	}
 	h.proto = resp
+	if resp.HttpErrorStatusCode != nil && (resp.GetHttpErrorStatusCode() < 200 || resp.GetHttpErrorStatusCode() > 299) {
+		aErr := &googleapi.Error{
+			Code: int(resp.GetHttpErrorStatusCode()),
+			Message: resp.GetHttpErrorMessage(),
+		}
+		err, _ := apierror.FromError(aErr)
+		return err
+	}
 	return nil
 }
 
diff --git a/rules_go_gapic/go_gapic.bzl b/rules_go_gapic/go_gapic.bzl
index 08166b99..f1a52d99 100644
--- a/rules_go_gapic/go_gapic.bzl
+++ b/rules_go_gapic/go_gapic.bzl
@@ -155,6 +155,7 @@ def go_gapic_library(
 
   actual_deps = deps + [
     "@com_github_googleapis_gax_go_v2//:go_default_library",
+    "@com_github_googleapis_gax_go_v2//apierror:go_default_library",
     "@org_golang_google_api//googleapi:go_default_library",
     "@org_golang_google_api//option:go_default_library",
     "@org_golang_google_api//option/internaloption:go_default_library",