diff --git a/src/chain.h b/src/chain.h
index a9417027d..4dfa58ec9 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -108,7 +108,7 @@ struct CDiskBlockPos
 
 };
 
-enum BlockStatus {
+enum BlockStatus: uint32_t {
     //! Unused.
     BLOCK_VALID_UNKNOWN      =    0,