diff --git a/lib/utils.js b/lib/utils.js
index 54320b4..1028fb5 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -1,5 +1,8 @@
 'use strict';
+
 var _ = require('lodash');
+var async = require('async');
+var common = require('./common');
 
 function UtilsController(node) {
   this.node = node;
@@ -10,14 +13,22 @@ UtilsController.prototype.estimateFee = function(req, res) {
   var args = req.query.nbBlocks || '2';
   var nbBlocks = args.split(',');
 
-  var result = nbBlocks.map(function(n) {
+  async.map(nbBlocks, function(n, next) {
     var num = parseInt(n);
     // Insight and Bitcoin JSON-RPC return bitcoin for this value (instead of satoshis).
-    var fee = self.node.services.bitcoind.estimateFee(num) / 1e8;
-    return [num, fee];
+    self.node.services.bitcoind.estimateFee(num, function(err, fee) {
+      if (err) {
+        return next(err);
+      }
+      next(null, [num, fee]);
+    });
+  }, function(err, result) {
+    if (err) {
+      return common.handleErrors(err, res);
+    }
+    res.jsonp(_.zipObject(result));
   });
 
-  res.jsonp(_.zipObject(result));
 };
 
 module.exports = UtilsController;
diff --git a/test/utils.js b/test/utils.js
index 4fda011..41c84a9 100644
--- a/test/utils.js
+++ b/test/utils.js
@@ -10,12 +10,12 @@ describe('Utils', function() {
       var node = {
         services: {
           bitcoind: {
-            estimateFee: function(blocks) {
+            estimateFee: function(blocks, callback) {
               switch(blocks) {
-                case 1:
-                  return 1000;
-                case 3:
-                  return 3000;
+              case 1:
+                return callback(null, 1000 / 1e8);
+              case 3:
+                return callback(null, 3000 / 1e8);
               }
             }
           }