diff --git a/pb_decode.c b/pb_decode.c
index 28f6b57..5f3b51e 100644
--- a/pb_decode.c
+++ b/pb_decode.c
@@ -530,8 +530,17 @@
                 memset(field->pData, 0, (size_t)field->data_size);
 
                 /* Set default values for the submessage fields. */
-                if (!pb_field_set_to_default(field))
-                    PB_RETURN_ERROR(stream, "failed to set defaults");
+                if (field->submsg_desc->default_value != NULL ||
+                    field->submsg_desc->field_callback != NULL ||
+                    field->submsg_desc->submsg_info[0] != NULL)
+                {
+                    pb_field_iter_t submsg_iter;
+                    if (pb_field_iter_begin(&submsg_iter, field->submsg_desc, field->pData))
+                    {
+                        if (!pb_message_set_to_defaults(&submsg_iter))
+                            PB_RETURN_ERROR(stream, "failed to set defaults");
+                    }
+                }
             }
             *(pb_size_t*)field->pSize = field->tag;
 
diff --git a/tests/alltypes/decode_alltypes.c b/tests/alltypes/decode_alltypes.c
index e431f35..8e70d86 100644
--- a/tests/alltypes/decode_alltypes.c
+++ b/tests/alltypes/decode_alltypes.c
@@ -213,6 +213,7 @@
         TEST(alltypes.which_oneof == AllTypes_oneof_msg1_tag);
         TEST(strcmp(alltypes.oneof.oneof_msg1.substuff1, "4059") == 0);
         TEST(alltypes.oneof.oneof_msg1.substuff2 == 4059);
+        TEST(alltypes.oneof.oneof_msg1.substuff3 == 3);
 
         TEST(alltypes.has_opt_non_zero_based_enum == true);
         TEST(alltypes.opt_non_zero_based_enum == NonZeroBasedEnum_Three);