diff --git a/xulrunner/post-install b/xulrunner/post-install
index c2af5f9d6..bfeb5b280 100755
--- a/xulrunner/post-install
+++ b/xulrunner/post-install
@@ -1,4 +1,6 @@
 #!/bin/sh
 
-/bin/echo "/usr/lib/xulrunner" >> /etc/ld.so.conf
-/sbin/ldconfig
+if [ -z "`grep "usr/lib/xulrunner" /etc/ld.so.conf`" ]; then
+	/bin/echo "/usr/lib/xulrunner" >> /etc/ld.so.conf
+	/sbin/ldconfig
+fi