diff --git a/pkgs/development/libraries/gstreamer/core/setup-hook.sh b/pkgs/development/libraries/gstreamer/core/setup-hook.sh
index b8c741af578f..026a4e5f55a0 100644
--- a/pkgs/development/libraries/gstreamer/core/setup-hook.sh
+++ b/pkgs/development/libraries/gstreamer/core/setup-hook.sh
@@ -1,7 +1,7 @@
 addGstreamer1LibPath () {
     if test -d "$1/lib/gstreamer-1.0"
     then
-        export GST_PLUGIN_SYSTEM_PATH_1_0="${GST_PLUGIN_SYSTEM_PATH_1_0}${GST_PLUGIN_SYSTEM_PATH_1_0:+:}$1/lib/gstreamer-1.0"
+        export GST_PLUGIN_SYSTEM_PATH_1_0="${GST_PLUGIN_SYSTEM_PATH_1_0-}${GST_PLUGIN_SYSTEM_PATH_1_0:+:}$1/lib/gstreamer-1.0"
     fi
 }
 
diff --git a/pkgs/development/libraries/gstreamer/legacy/gstreamer/setup-hook.sh b/pkgs/development/libraries/gstreamer/legacy/gstreamer/setup-hook.sh
index 65ce26112519..636e20b732b4 100644
--- a/pkgs/development/libraries/gstreamer/legacy/gstreamer/setup-hook.sh
+++ b/pkgs/development/libraries/gstreamer/legacy/gstreamer/setup-hook.sh
@@ -1,7 +1,7 @@
 addGstreamerLibPath () {
     if test -d "$1/lib/gstreamer-0.10"
     then
-        export GST_PLUGIN_SYSTEM_PATH="${GST_PLUGIN_SYSTEM_PATH}${GST_PLUGIN_SYSTEM_PATH:+:}$1/lib/gstreamer-0.10"
+        export GST_PLUGIN_SYSTEM_PATH="${GST_PLUGIN_SYSTEM_PATH-}${GST_PLUGIN_SYSTEM_PATH:+:}$1/lib/gstreamer-0.10"
     fi
 }