diff --git a/src/wallet.js b/src/wallet.js
index ef1405a..a89cd75 100644
--- a/src/wallet.js
+++ b/src/wallet.js
@@ -84,13 +84,14 @@ var Wallet = function (seed, options) {
     }
 
     this.setUnspentOutputsAsync = function(utxo, callback) {
+      var error = null
       try {
         this.setUnspentOutputs(utxo)
       } catch(err) {
-        return callback(err)
+        error = err
+      } finally {
+        process.nextTick(function(){ callback(error) })
       }
-
-      return callback()
     }
 
     function outputToUnspentOutput(output){
@@ -206,14 +207,15 @@ var Wallet = function (seed, options) {
         fixedFee = undefined
       }
       var tx = null
+      var error = null
 
       try {
         tx = this.createTx(to, value, fixedFee)
       } catch(err) {
-        return callback(err)
+        error = err
+      } finally {
+        process.nextTick(function(){ callback(error, tx) })
       }
-
-      callback(null, tx)
     }
 
     this.dustThreshold = 5430
diff --git a/test/wallet.js b/test/wallet.js
index f19bc3b..fb5ba1e 100644
--- a/test/wallet.js
+++ b/test/wallet.js
@@ -284,24 +284,25 @@ describe('Wallet', function() {
         wallet.setUnspentOutputs.restore()
       })
 
-      it('calls setUnspentOutputs', function(){
+      it('calls setUnspentOutputs', function(done){
         sinon.stub(wallet, "setUnspentOutputs")
 
-        var callback = sinon.spy()
-        var tx = wallet.setUnspentOutputsAsync(utxo, callback)
+        var callback = function(){
+          assert(wallet.setUnspentOutputs.calledWith(utxo))
+          done()
+        }
 
-        assert(wallet.setUnspentOutputs.calledWith(utxo))
-        assert(callback.called)
+        wallet.setUnspentOutputsAsync(utxo, callback)
       })
 
-      it('when setUnspentOutputs throws an error, it invokes callback with error', function(){
+      it('when setUnspentOutputs throws an error, it invokes callback with error', function(done){
         sinon.stub(wallet, "setUnspentOutputs").throws()
 
-        var callback = sinon.spy()
-        var tx = wallet.setUnspentOutputsAsync(utxo, callback)
-
-        assert(callback.called)
-        assert(callback.args[0][0] instanceof Error)
+        var callback = function(err){
+          assert(err instanceof Error)
+          done()
+        }
+        wallet.setUnspentOutputsAsync(utxo, callback)
       })
     })
   })
@@ -549,34 +550,41 @@ describe('Wallet', function() {
       wallet.createTx.restore()
     })
 
-    it('calls createTx', function(){
+    it('calls createTx', function(done){
       sinon.stub(wallet, "createTx").returns("fakeTx")
 
-      var callback = sinon.spy()
-      var tx = wallet.createTxAsync(to, value, callback)
+      var callback = function(err, tx){
+        assert(wallet.createTx.calledWith(to, value))
+        assert.equal(err, null)
+        assert.equal(tx, "fakeTx")
+        done()
+      }
 
-      assert(wallet.createTx.calledWith(to, value))
-      assert(callback.calledWith(null, "fakeTx"))
+      wallet.createTxAsync(to, value, callback)
     })
 
-    it('calls createTx correctly when fee is specified', function(){
+    it('calls createTx correctly when fee is specified', function(done){
       sinon.stub(wallet, "createTx").returns("fakeTx")
 
-      var callback = sinon.spy()
-      var tx = wallet.createTxAsync(to, value, fee, callback)
+      var callback = function(err, tx){
+        assert(wallet.createTx.calledWith(to, value, fee))
+        assert.equal(err, null)
+        assert.equal(tx, "fakeTx")
+        done()
+      }
 
-      assert(wallet.createTx.calledWith(to, value, fee))
-      assert(callback.calledWith(null, "fakeTx"))
+      wallet.createTxAsync(to, value, fee, callback)
     })
 
-    it('when createTx throws an error, it invokes callback with error', function(){
+    it('when createTx throws an error, it invokes callback with error', function(done){
       sinon.stub(wallet, "createTx").throws()
 
-      var callback = sinon.spy()
-      var tx = wallet.createTxAsync(to, value, callback)
+      var callback = function(err, tx){
+        assert(err instanceof Error)
+        done()
+      }
 
-      assert(callback.called)
-      assert(callback.args[0][0] instanceof Error)
+      wallet.createTxAsync(to, value, callback)
     })
   })