diff --git a/include/rocksdb/slice.h b/include/rocksdb/slice.h
index 406a8abb9ab4b742e3ec33ec607e887447b660cf..05d0f9df6c89b9f7b85489b5d2bec51b52c18a6c 100644
--- a/include/rocksdb/slice.h
+++ b/include/rocksdb/slice.h
@@ -123,7 +123,7 @@ inline bool operator!=(const Slice& x, const Slice& y) {
 }
 
 inline int Slice::compare(const Slice& b) const {
-  const int min_len = (size_ < b.size_) ? size_ : b.size_;
+  const size_t min_len = (size_ < b.size_) ? size_ : b.size_;
   int r = memcmp(data_, b.data_, min_len);
   if (r == 0) {
     if (size_ < b.size_) r = -1;