diff --git a/istl/io.hh b/istl/io.hh
index 2175ce5d18df4a1534e97186e966b9f8854aecb9..ae2cec92bb9fca7cc5074aa5ca39bb2a29ba7827 100644
--- a/istl/io.hh
+++ b/istl/io.hh
@@ -219,7 +219,7 @@ namespace Dune {
    * together with their
    * corresponding column index and all others will be omitted.
    *
-   * This might be perferable over printmatrix in the case of big
+   * This might be preferable over printmatrix in the case of big
    * sparse matrices with nonscalar blocks.
    *
    * @param s The ostream to print to.