diff --git a/istl/ilu.hh b/istl/ilu.hh
index 6fcc3a6c6d458425f69c63d854dee9896e4c4596..4441bdb89d0028018f0754793194fe2b650b28d7 100644
--- a/istl/ilu.hh
+++ b/istl/ilu.hh
@@ -163,8 +163,8 @@ namespace Dune {
     typedef typename M::CreateIterator createiterator;
     typedef typename M::block_type block;
     typedef typename M::field_type K;
-    typedef typename std::map<int,int> map;
-    typedef typename std::map<int,int>::iterator mapiterator;
+    typedef std::map<size_t, int> map;
+    typedef typename map::iterator mapiterator;
 
     // symbolic factorization phase, store generation number in first matrix element
     crowiterator endi=A.end();