diff --git a/lib/6to5/transformation/transformers/es6/constants.js b/lib/6to5/transformation/transformers/es6/constants.js
index a58cd16256..f559a2cccc 100644
--- a/lib/6to5/transformation/transformers/es6/constants.js
+++ b/lib/6to5/transformation/transformers/es6/constants.js
@@ -10,6 +10,8 @@ exports.check = function (node) {
 var visitor = {
   enter: function (node, parent, scope, state) {
     if (t.isAssignmentExpression(node) || t.isUpdateExpression(node)) {
+      if (t.isMemberExpression(node.left || node.argument)) return;
+
       var ids = t.getBindingIdentifiers(node);
 
       for (var name in ids) {
diff --git a/test/fixtures/transformation/es6-constants/ignore-member-expressions/actual.js b/test/fixtures/transformation/es6-constants/ignore-member-expressions/actual.js
new file mode 100644
index 0000000000..50ead66453
--- /dev/null
+++ b/test/fixtures/transformation/es6-constants/ignore-member-expressions/actual.js
@@ -0,0 +1,2 @@
+const x = {};
+x.key = "value";
diff --git a/test/fixtures/transformation/es6-constants/ignore-member-expressions/expected.js b/test/fixtures/transformation/es6-constants/ignore-member-expressions/expected.js
new file mode 100644
index 0000000000..f78bd701f4
--- /dev/null
+++ b/test/fixtures/transformation/es6-constants/ignore-member-expressions/expected.js
@@ -0,0 +1,4 @@
+"use strict";
+
+var x = {};
+x.key = "value";