diff --git a/ompi/mca/mpool/mpool.h b/ompi/mca/mpool/mpool.h
index ad3b6dbe7d..e6ae5a596d 100644
--- a/ompi/mca/mpool/mpool.h
+++ b/ompi/mca/mpool/mpool.h
@@ -39,7 +39,7 @@ struct mca_mpool_base_registration_t {
     unsigned char* bound; 
     unsigned char* alloc_base;
     void* user_data; 
-    uint32_t ref_count; 
+    int32_t ref_count; 
     uint32_t flags;
 };