diff --git a/src/heap_utils.cc b/src/heap_utils.cc
index 0a68077d5d9b24..467e7ee5f82692 100644
--- a/src/heap_utils.cc
+++ b/src/heap_utils.cc
@@ -245,7 +245,7 @@ class FileOutputStream : public v8::OutputStream {
         status_ = num_bytes_written;
         return kAbort;
       }
-      DCHECK_LE(num_bytes_written, buf.len);
+      DCHECK_LE(static_cast<size_t>(num_bytes_written), buf.len);
       offset += num_bytes_written;
     }
     DCHECK_EQ(offset, size);