diff --git a/bin/compile b/bin/compile
index 788e64188b5418ef29d91beb90762dbe6287582e..173f16b969c50f2467226011fb6db549e2f38763 100755
--- a/bin/compile
+++ b/bin/compile
@@ -207,15 +207,16 @@ for dir in $CACHED_DIRS; do
 done
 
 # Set context environment variables.
-
-set-env PATH '$HOME/.heroku/venv/bin:$PATH'
-set-default-env PYTHONUNBUFFERED true
-set-default-env LIBRARY_PATH /app/.heroku/vendor/lib
-set-default-env LD_LIBRARY_PATH /app/.heroku/vendor/lib
-set-default-env LANG en_US.UTF-8
-set-default-env PYTHONHASHSEED random
-set-default-env PYTHONHOME /app/.heroku/venv/
-set-default-env PYTHONPATH /app/
+if [ ! -n "$LEGACY_VIRTUALENV" ]; then
+  set-env PATH '$HOME/.heroku/venv/bin:$PATH'
+  set-default-env PYTHONUNBUFFERED true
+  set-default-env LIBRARY_PATH /app/.heroku/vendor/lib
+  set-default-env LD_LIBRARY_PATH /app/.heroku/vendor/lib
+  set-default-env LANG en_US.UTF-8
+  set-default-env PYTHONHASHSEED random
+  set-default-env PYTHONHOME /app/.heroku/venv/
+  set-default-env PYTHONPATH /app/
+fi
 
 # ### Fin.