diff --git a/lib/services/address/index.js b/lib/services/address/index.js
index df2a593c..873e272c 100644
--- a/lib/services/address/index.js
+++ b/lib/services/address/index.js
@@ -1048,8 +1048,12 @@ AddressService.prototype.getUnspentOutputsForAddress = function(address, queryMe
       return callback(new errors.NoOutputs('Address ' + address + ' has no outputs'), []);
     }
 
+    var opts = {
+      queryMempool: queryMempool
+    };
+
     var isUnspent = function(output, callback) {
-      self.isUnspent(output, callback);
+      self.isUnspent(output, opts, callback);
     };
 
     async.filter(outputs, isUnspent, function(results) {
@@ -1061,25 +1065,37 @@ AddressService.prototype.getUnspentOutputsForAddress = function(address, queryMe
 /**
  * Will give the inverse of isSpent
  * @param {Object} output
+ * @param {Object} options
+ * @param {Boolean} options.queryMempool - Include mempool in results
  * @param {Function} callback
  */
-AddressService.prototype.isUnspent = function(output, callback) {
-  this.isSpent(output, function(spent) {
+AddressService.prototype.isUnspent = function(output, options, callback) {
+  $.checkArgument(_.isFunction(callback));
+  this.isSpent(output, options, function(spent) {
     callback(!spent);
   });
 };
 
 /**
- * Will determine if an output is spent, results do not include the mempool.
+ * Will determine if an output is spent.
  * @param {Object} output - An output as returned from getOutputs
+ * @param {Object} options
+ * @param {Boolean} options.queryMempool - Include mempool in results
  * @param {Function} callback
  */
-AddressService.prototype.isSpent = function(output, callback) {
+AddressService.prototype.isSpent = function(output, options, callback) {
+  $.checkArgument(_.isFunction(callback));
+  var queryMempool = _.isUndefined(options.queryMempool) ? true : options.queryMempool;
   var self = this;
   var txid = output.prevTxId ? output.prevTxId.toString('hex') : output.txid;
-
+  var spent = self.node.services.bitcoind.isSpent(txid, output.outputIndex);
+  if (!spent && queryMempool) {
+    var spentIndexKey = [txid, output.outputIndex].join('-');
+    spent = self.mempoolSpentIndex[spentIndexKey] ? true : false;
+  }
   setImmediate(function() {
-    callback(self.node.services.bitcoind.isSpent(txid, output.outputIndex));
+    // TODO error should be the first argument?
+    callback(spent);
   });
 };
 
@@ -1179,7 +1195,7 @@ AddressService.prototype.getAddressSummary = function(address, options, callback
       var txids = [];
 
       for(var i = 0; i < outputs.length; i++) {
-        // Bitcoind's isSpent at the moment only works for confirmed transactions
+        // Bitcoind's isSpent only works for confirmed transactions
         var spentDB = self.node.services.bitcoind.isSpent(outputs[i].txid, outputs[i].outputIndex);
         var spentIndexKey = [outputs[i].txid, outputs[i].outputIndex].join('-');
         var spentMempool = self.mempoolSpentIndex[spentIndexKey];
diff --git a/test/services/address/index.unit.js b/test/services/address/index.unit.js
index 17655b49..5add2cce 100644
--- a/test/services/address/index.unit.js
+++ b/test/services/address/index.unit.js
@@ -872,7 +872,7 @@ describe('Address Service', function() {
 
       var am = new AddressService({node: mocknode});
       am.getOutputs = sinon.stub().callsArgWith(2, null, outputs);
-      am.isUnspent = function(output, callback) {
+      am.isUnspent = function(output, options, callback) {
         callback(!outputs[i].spent);
         i++;
       };
@@ -914,24 +914,24 @@ describe('Address Service', function() {
     });
 
     it('should give true when isSpent() gives false', function(done) {
-      am.isSpent = sinon.stub().callsArgWith(1, false);
-      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', function(unspent) {
+      am.isSpent = sinon.stub().callsArgWith(2, false);
+      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', {}, function(unspent) {
         unspent.should.equal(true);
         done();
       });
     });
 
     it('should give false when isSpent() gives true', function(done) {
-      am.isSpent = sinon.stub().callsArgWith(1, true);
-      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', function(unspent) {
+      am.isSpent = sinon.stub().callsArgWith(2, true);
+      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', {},function(unspent) {
         unspent.should.equal(false);
         done();
       });
     });
 
     it('should give false when isSpent() returns an error', function(done) {
-      am.isSpent = sinon.stub().callsArgWith(1, new Error('error'));
-      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', function(unspent) {
+      am.isSpent = sinon.stub().callsArgWith(2, new Error('error'));
+      am.isUnspent('1KiW1A4dx1oRgLHtDtBjcunUGkYtFgZ1W', {}, function(unspent) {
         unspent.should.equal(false);
         done();
       });
@@ -939,7 +939,6 @@ describe('Address Service', function() {
   });
 
   describe('#isSpent', function() {
-    var am;
     var db = {};
     var testnode = {
       db: db,
@@ -949,16 +948,70 @@ describe('Address Service', function() {
         }
       }
     };
-    before(function() {
-      am = new AddressService({node: testnode});
+    it('should give true if bitcoind.isSpent gives true', function(done) {
+      var am = new AddressService({node: testnode});
       am.node.services.bitcoind = {
         isSpent: sinon.stub().returns(true),
         on: sinon.stub()
       };
+      am.isSpent({}, {}, function(spent) {
+        spent.should.equal(true);
+        done();
+      });
     });
-
-    it('should give true if bitcoind.isSpent gives true', function(done) {
-      am.isSpent('output', function(spent) {
+    it('should give true if bitcoind.isSpent is false and mempoolSpentIndex is true', function(done) {
+      var am = new AddressService({node: testnode});
+      am.node.services.bitcoind = {
+        isSpent: sinon.stub().returns(false),
+        on: sinon.stub()
+      };
+      var txid = '3b6bc2939d1a70ce04bc4f619ee32608fbff5e565c1f9b02e4eaa97959c59ae7';
+      var outputIndex = 0;
+      var output = {
+        prevTxId: new Buffer(txid, 'hex'),
+        outputIndex: outputIndex
+      };
+      var spentKey = [txid, outputIndex].join('-');
+      am.mempoolSpentIndex[spentKey] = new Buffer(5);
+      am.isSpent(output, {queryMempool: true}, function(spent) {
+        spent.should.equal(true);
+        done();
+      });
+    });
+    it('should give false if spent in mempool with queryMempool set to false', function(done) {
+      var am = new AddressService({node: testnode});
+      am.node.services.bitcoind = {
+        isSpent: sinon.stub().returns(false),
+        on: sinon.stub()
+      };
+      var txid = '3b6bc2939d1a70ce04bc4f619ee32608fbff5e565c1f9b02e4eaa97959c59ae7';
+      var outputIndex = 0;
+      var output = {
+        prevTxId: new Buffer(txid, 'hex'),
+        outputIndex: outputIndex
+      };
+      var spentKey = [txid, outputIndex].join('-');
+      am.mempoolSpentIndex[spentKey] = new Buffer(5);
+      am.isSpent(output, {queryMempool: false}, function(spent) {
+        spent.should.equal(false);
+        done();
+      });
+    });
+    it('default to querying the mempool', function(done) {
+      var am = new AddressService({node: testnode});
+      am.node.services.bitcoind = {
+        isSpent: sinon.stub().returns(false),
+        on: sinon.stub()
+      };
+      var txid = '3b6bc2939d1a70ce04bc4f619ee32608fbff5e565c1f9b02e4eaa97959c59ae7';
+      var outputIndex = 0;
+      var output = {
+        prevTxId: new Buffer(txid, 'hex'),
+        outputIndex: outputIndex
+      };
+      var spentKey = [txid, outputIndex].join('-');
+      am.mempoolSpentIndex[spentKey] = new Buffer(5);
+      am.isSpent(output, {}, function(spent) {
         spent.should.equal(true);
         done();
       });