diff --git a/encode_value.go b/encode_value.go
index 681dc691..33e21e2a 100644
--- a/encode_value.go
+++ b/encode_value.go
@@ -192,6 +192,14 @@ func encodeErrorValue(e *Encoder, v reflect.Value) error {
 	if v.IsNil() {
 		return e.EncodeNil()
 	}
+
+	// Preserve a concrete custom encoder stored in an error interface. The
+	// default error representation remains a string for ordinary errors.
+	concrete := v.Elem()
+	if concrete.IsValid() && concrete.Type().Implements(customEncoderType) {
+		return e.EncodeValue(concrete)
+	}
+
 	return e.EncodeString(v.Interface().(error).Error())
 }
 
diff --git a/types_test.go b/types_test.go
index 3b4f1d32..9a30b7bd 100644
--- a/types_test.go
+++ b/types_test.go
@@ -117,6 +117,23 @@ type CustomEncoderEmbeddedPtr struct {
 	*CustomEncoder
 }
 
+type customError struct {
+	code    string
+	message string
+}
+
+func (e *customError) Error() string {
+	return e.code + ": " + e.message
+}
+
+func (e *customError) EncodeMsgpack(enc *msgpack.Encoder) error {
+	return enc.EncodeMulti(e.code, e.message)
+}
+
+func (e *customError) DecodeMsgpack(dec *msgpack.Decoder) error {
+	return dec.DecodeMulti(&e.code, &e.message)
+}
+
 func (s *CustomEncoderEmbeddedPtr) DecodeMsgpack(dec *msgpack.Decoder) error {
 	if s.CustomEncoder == nil {
 		s.CustomEncoder = new(CustomEncoder)
@@ -124,6 +141,19 @@ func (s *CustomEncoderEmbeddedPtr) DecodeMsgpack(dec *msgpack.Decoder) error {
 	return s.CustomEncoder.DecodeMsgpack(dec)
 }
 
+func TestCustomErrorInInterfaceSlice(t *testing.T) {
+	input := []error{&customError{code: "E42", message: "quota exceeded"}}
+	b, err := msgpack.Marshal(input)
+	require.NoError(t, err)
+
+	output := []error{&customError{}}
+	require.NoError(t, msgpack.Unmarshal(b, &output))
+
+	got, ok := output[0].(*customError)
+	require.True(t, ok, "custom error should retain its concrete type")
+	require.Equal(t, input[0].Error(), got.Error())
+}
+
 //------------------------------------------------------------------------------
 
 type JSONFallbackTest struct {