diff --git a/contrib/ChangeLog b/contrib/ChangeLog
index 5fa6e032be4..45ccc164756 100644
--- a/contrib/ChangeLog
+++ b/contrib/ChangeLog
@@ -1,3 +1,7 @@
+2017-09-18  Richard Biener  <rguenther@suse.de>
+
+	* download_prerequisites (isl): Bump version to 0.18.
+
 2017-08-02  Yury Gribov  <tetra2005@gmail.com>
 
 	* mklog: Added new implementation.
diff --git a/contrib/download_prerequisites b/contrib/download_prerequisites
index 3430ce1f19e..ae0b5ffeb32 100755
--- a/contrib/download_prerequisites
+++ b/contrib/download_prerequisites
@@ -30,7 +30,7 @@ version='(unversioned)'
 gmp='gmp-6.1.0.tar.bz2'
 mpfr='mpfr-3.1.4.tar.bz2'
 mpc='mpc-1.0.3.tar.gz'
-isl='isl-0.16.1.tar.bz2'
+isl='isl-0.18.tar.bz2'
 
 base_url='ftp://gcc.gnu.org/pub/gcc/infrastructure/'