diff --git a/gmatch4py/helpers/compute_similarity_matrix.pyx b/gmatch4py/helpers/compute_similarity_matrix.pyx
index 382e74286548eb75e5340137a4d26143d632e7f4..fa627820a771b8b6f642a6f04392c1d58fd205dd 100644
--- a/gmatch4py/helpers/compute_similarity_matrix.pyx
+++ b/gmatch4py/helpers/compute_similarity_matrix.pyx
@@ -139,7 +139,7 @@ def run(config_filename):
     if not os.path.exists(config.output_dir):
         print("Output matrix directory doesn't exist!")
         print("Creating directory")
-        os.makedirs(args.output_dir)
+        os.makedirs(config.output_dir)
         print("Directory created")
 
     selected=None