diff --git a/lib/6to5/traverse/scope.js b/lib/6to5/traverse/scope.js
index 1781ffca9d..9039501e0c 100644
--- a/lib/6to5/traverse/scope.js
+++ b/lib/6to5/traverse/scope.js
@@ -37,6 +37,8 @@ Scope.prototype.getIds = function () {
         return false;
       }
     });
+  } else if (t.isCatchClause(block)) {
+    self.add(block.param, ids);
   }
 
   if (t.isFunction(block)) {
diff --git a/lib/6to5/types/alias-keys.json b/lib/6to5/types/alias-keys.json
index 90de64c757..55a5af6e65 100644
--- a/lib/6to5/types/alias-keys.json
+++ b/lib/6to5/types/alias-keys.json
@@ -23,6 +23,7 @@
 
   "BlockStatement": ["Statement", "Scope"],
   "Program":        ["Scope"],
+  "CatchClause":    ["Scope"],
 
   "LogicalExpression": ["Binary"],
   "BinaryExpression":  ["Binary"],