diff --git a/lib/emailservice.js b/lib/emailservice.js
index e5ad0d8..aa6e994 100644
--- a/lib/emailservice.js
+++ b/lib/emailservice.js
@@ -204,58 +204,69 @@ EmailService.prototype.sendEmail = function(notification, cb) {
   self._getRecipientsList(notification, emailType, function(err, recipientsList) {
     if (_.isEmpty(recipientsList)) return cb();
 
-    async.waterfall([
+    // TODO: Optimize so one process does not have to wait until all others are done
+    // Instead set a flag somewhere in the db to indicate that this process is free
+    // to serve another request.
+    self.lock.runLocked('email-' + notification.id, cb, function(cb) {
+      self.storage.fetchEmailByNotification(notification.id, function(err, email) {
+        if (err) return cb(err);
+        if (email) return cb();
 
-      function(next) {
-        async.parallel([
+        async.waterfall([
 
           function(next) {
-            self._readTemplate(emailType.filename, next);
+            async.parallel([
+
+              function(next) {
+                self._readTemplate(emailType.filename, next);
+              },
+              function(next) {
+                self._getDataForTemplate(notification, next);
+              },
+            ], function(err, res) {
+              next(err, res[0], res[1]);
+            });
           },
-          function(next) {
-            self._getDataForTemplate(notification, next);
+          function(template, data, next) {
+            self._applyTemplate(template, data, next);
           },
-        ], function(err, res) {
-          next(err, res[0], res[1]);
+          function(content, next) {
+            async.map(recipientsList, function(recipient, next) {
+              var email = Model.Email.create({
+                walletId: notification.walletId,
+                copayerId: recipient.copayerId,
+                from: self.from,
+                to: recipient.emailAddress,
+                subject: content.subject,
+                body: content.body,
+                notificationId: notification.id,
+              });
+              self.storage.storeEmail(email, function(err) {
+                return next(err, email);
+              });
+            }, next);
+          },
+          function(emails, next) {
+            async.each(emails, function(email, next) {
+              self._send(email, function(err) {
+                if (err) {
+                  email.setFail();
+                } else {
+                  email.setSent();
+                }
+                self.storage.storeEmail(email, next);
+              });
+            }, function(err) {
+              return next();
+            });
+          },
+        ], function(err) {
+          if (err) {
+            log.error('An error ocurred generating email notification', err);
+          }
+          return cb(err);
         });
-      },
-      function(template, data, next) {
-        self._applyTemplate(template, data, next);
-      },
-      function(content, next) {
-        async.map(recipientsList, function(recipient, next) {
-          var email = Model.Email.create({
-            walletId: notification.walletId,
-            copayerId: recipient.copayerId,
-            from: self.from,
-            to: recipient.emailAddress,
-            subject: content.subject,
-            body: content.body,
-          });
-          self.storage.storeEmail(email, function(err) {
-            return next(err, email);
-          });
-        }, next);
-      },
-      function(emails, next) {
-        async.each(emails, function(email, next) {
-          self._send(email, function(err) {
-            if (err) {
-              email.setFail();
-            } else {
-              email.setSent();
-            }
-            self.storage.storeEmail(email, next);
-          });
-        }, function(err) {
-          return next();
-        });
-      },
-    ], function(err) {
-      if (err) {
-        log.error('An error ocurred generating email notification', err);
-      }
-      return cb(err);
+      });
     });
   });
 };
diff --git a/lib/model/email.js b/lib/model/email.js
index 2d30f07..63140bb 100644
--- a/lib/model/email.js
+++ b/lib/model/email.js
@@ -24,6 +24,7 @@ Email.create = function(opts) {
   x.status = 'pending';
   x.attempts = 0;
   x.lastAttemptOn = null;
+  x.notificationId = opts.notificationId;
   return x;
 };
 
@@ -41,6 +42,7 @@ Email.fromObj = function(obj) {
   x.status = obj.status;
   x.attempts = obj.attempts;
   x.lastAttemptOn = obj.lastAttemptOn;
+  x.notificationId = obj.notificationId;
   return x;
 };
 
diff --git a/lib/storage.js b/lib/storage.js
index ead5b29..19eee01 100644
--- a/lib/storage.js
+++ b/lib/storage.js
@@ -52,6 +52,9 @@ Storage.prototype._createIndexes = function() {
   this.db.collection(collections.ADDRESSES).createIndex({
     address: 1,
   });
+  this.db.collection(collections.EMAIL_QUEUE).createIndex({
+    notificationId: 1,
+  });
 };
 
 Storage.prototype.connect = function(opts, cb) {
@@ -407,6 +410,16 @@ Storage.prototype.fetchUnsentEmails = function(cb) {
   });
 };
 
+Storage.prototype.fetchEmailByNotification = function(notificationId, cb) {
+  this.db.collection(collections.EMAIL_QUEUE).findOne({
+    notificationId: notificationId,
+  }, function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+
+    return cb(null, Model.Email.fromObj(result));
+  });
+};
 
 Storage.prototype._dump = function(cb, fn) {
   fn = fn || console.log;
diff --git a/test/integration/server.js b/test/integration/server.js
index 36a3f7c..78b759e 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -497,10 +497,10 @@ describe('Wallet service', function() {
       });
     });
 
-    it.only('should support multiple emailservice instances running concurrently', function(done) {
+    it('should support multiple emailservice instances running concurrently', function(done) {
       var emailService2 = new EmailService();
       emailService2.start({
-        lockOpts: {},
+        lock: emailService.lock, // Use same locker service
         messageBroker: server.messageBroker,
         storage: storage,
         mailer: mailerStub,