diff --git a/dune/common/fvector.hh b/dune/common/fvector.hh
index 9dbfd8c0a6dbf5a6a6861ebe646c89718ca6fc08..4a69364f741e62decc9a2d69acb03e17a8cecbdc 100644
--- a/dune/common/fvector.hh
+++ b/dune/common/fvector.hh
@@ -80,7 +80,7 @@ namespace Dune {
 
     //! Constructor making vector with identical coordinates
     template<class C>
-    FieldVector (const DenseVector<C> & x)
+    explicit FieldVector (const DenseVector<C> & x)
     {
       assert(x.size() == SIZE);
       for (size_type i = 0; i<SIZE; i++)