diff --git a/.gitignore b/.gitignore
index a35dc06b8c0dbb4f58a3e94e98870c45978dfd61..0d1fa198833f0b280c75d182a51c3e59fd2f0d54 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,6 @@
 target
 /project/build
 /leon
+
+# synthesis
+derivation*.dot