diff --git a/lib/unit.js b/lib/unit.js
index f51eda6cd..45a2dfdf3 100644
--- a/lib/unit.js
+++ b/lib/unit.js
@@ -187,7 +187,7 @@ Unit.prototype.toObject = function toObject() {
 };
 
 Unit.prototype.toJSON = function toJSON() {
-  return this.toObject();
+  return JSON.stringify(this.toObject());
 };
 
 /**
diff --git a/test/unit.js b/test/unit.js
index 87fc82fab..063fa6dd9 100644
--- a/test/unit.js
+++ b/test/unit.js
@@ -124,7 +124,7 @@ describe('Unit', function() {
   });
 
   it('should input/output JSON', function() {
-    var json = {amount:1.3, code:'BTC'};
+    var json = JSON.stringify({amount:1.3, code:'BTC'});
     var unit = Unit.fromJSON(json);
     unit.toJSON().should.deep.equal(json);
   });