diff --git a/src/protobuf.c b/src/protobuf.c
index 21959eceb10256bebf3e360f687afd7ac575d683..ca482d675ba588cf838ac5219607e3c5167ecc2c 100644
--- a/src/protobuf.c
+++ b/src/protobuf.c
@@ -1405,7 +1405,7 @@ parse_pbf_nodes (readosm_string_table * strings,
 		      for (; i_keys < packed_keys.count; i_keys++)
 			{
 			    /* decoding packed-keys */
-			    int is = *(packed_keys.values + i_keys);
+			    unsigned int is = *(packed_keys.values + i_keys);
 			    if (is == 0)
 			      {
 				  /* next Node */