diff --git a/bzip_extent_writer.cc b/bzip_extent_writer.cc
index e200e2d..9d432c7 100644
--- a/bzip_extent_writer.cc
+++ b/bzip_extent_writer.cc
@@ -50,7 +50,7 @@
                      output_buffer.size() - stream_.avail_out));
     
     if (rc == BZ_STREAM_END)
-      CHECK_EQ(stream_.avail_in, 0);
+      CHECK_EQ(stream_.avail_in, static_cast<unsigned int>(0));
     if (stream_.avail_in == 0)
       break;  // no more input to process
   }