diff --git a/simgear/io/untar.cxx b/simgear/io/untar.cxx
index f73bbfa3..c11686ed 100644
--- a/simgear/io/untar.cxx
+++ b/simgear/io/untar.cxx
@@ -348,6 +348,9 @@ public:
 
     ~GZTarExtractor()
     {
+        if (haveInitedZLib) {
+            inflateEnd(&zlibStream);
+        }
         free(zlibOutput);
     }