diff --git a/migrations/20160405083451-users-drop-username-null.js b/migrations/20160405083451-users-drop-username-null.js
new file mode 100644
index 000000000..aa941c5bb
--- /dev/null
+++ b/migrations/20160405083451-users-drop-username-null.js
@@ -0,0 +1,15 @@
+dbm = dbm || require('db-migrate');
+
+exports.up = function(db, callback) {
+    db.runSql('ALTER TABLE users MODIFY username VARCHAR(254) UNIQUE', [], function (error) {
+        if (error) console.error(error);
+        callback(error);
+    });
+};
+
+exports.down = function(db, callback) {
+    db.runSql('ALTER TABLE users MODIFY username VARCHAR(254) NOT NULL UNIQUE', [], function (error) {
+        if (error) console.error(error);
+        callback(error);
+    });
+};
diff --git a/migrations/schema.sql b/migrations/schema.sql
index 7c2e6617a..b5975c734 100644
--- a/migrations/schema.sql
+++ b/migrations/schema.sql
@@ -11,7 +11,7 @@
 
 CREATE TABLE IF NOT EXISTS users(
     id VARCHAR(128) NOT NULL UNIQUE,
-    username VARCHAR(254) NOT NULL UNIQUE,
+    username VARCHAR(254) UNIQUE,
     email VARCHAR(254) NOT NULL UNIQUE,
     password VARCHAR(1024) NOT NULL,
     salt VARCHAR(512) NOT NULL,
diff --git a/src/test/database-test.js b/src/test/database-test.js
index 50cbc9aa6..21fc65f55 100644
--- a/src/test/database-test.js
+++ b/src/test/database-test.js
@@ -47,7 +47,7 @@ describe('database', function () {
 
         var USER_1 = {
             id: 'uuid456',
-            username: 'uuid456',
+            username: '',
             password: 'secret',
             email: 'safe2@me.com',
             salt: 'tata',
@@ -57,18 +57,28 @@ describe('database', function () {
             displayName: 'Herbert Heidelberg'
         };
 
+        var USER_2 = {
+            id: 'uuid457',
+            username: '',
+            password: 'secret',
+            email: 'safe3@me.com',
+            salt: 'tata',
+            createdAt: 'sometime back',
+            modifiedAt: 'now',
+            resetToken: '',
+            displayName: 'Herbert Heidelberg'
+        };
+
         it('can add user', function (done) {
-            userdb.add(USER_0.id, USER_0, function (error) {
-                expect(!error).to.be.ok();
-                done();
-            });
+            userdb.add(USER_0.id, USER_0, done);
         });
 
         it('can add another user', function (done) {
-            userdb.add(USER_1.id, USER_1, function (error) {
-                expect(!error).to.be.ok();
-                done();
-            });
+            userdb.add(USER_1.id, USER_1, done);
+        });
+
+        it('can add another user with empty username', function (done) {
+            userdb.add(USER_2.id, USER_2, done);
         });
 
         it('cannot add same user again', function (done) {
@@ -123,13 +133,22 @@ describe('database', function () {
         it('can get all with group ids', function (done) {
             userdb.getAllWithGroupIds(function (error, all) {
                 expect(error).to.not.be.ok();
-                expect(all.length).to.equal(2);
-                var user0Copy = _.extend({}, USER_0);
-                user0Copy.groupIds = [ ];
-                expect(all[0]).to.eql(user0Copy);
-                var user1Copy = _.extend({}, USER_1);
-                user1Copy.groupIds = [ ];
-                expect(all[1]).to.eql(user1Copy);
+                expect(all.length).to.equal(3);
+
+                var userCopy;
+
+                userCopy = _.extend({}, USER_0);
+                userCopy.groupIds = [ ];
+                expect(all[0]).to.eql(userCopy);
+
+                userCopy = _.extend({}, USER_1);
+                userCopy.groupIds = [ ];
+                expect(all[1]).to.eql(userCopy);
+
+                userCopy = _.extend({}, USER_2);
+                userCopy.groupIds = [ ];
+                expect(all[2]).to.eql(userCopy);
+
                 done();
             });
         });
@@ -145,7 +164,7 @@ describe('database', function () {
         it('counts the users', function (done) {
             userdb.count(function (error, count) {
                 expect(error).to.not.be.ok();
-                expect(count).to.equal(2);
+                expect(count).to.equal(3);
                 done();
             });
         });
@@ -185,7 +204,7 @@ describe('database', function () {
 
         it('did remove the user', function (done) {
             userdb.count(function (error, count) {
-                expect(count).to.equal(1);
+                expect(count).to.equal(2);
                 done();
             });
         });
diff --git a/src/userdb.js b/src/userdb.js
index 78a21a5b4..8403ff6a2 100644
--- a/src/userdb.js
+++ b/src/userdb.js
@@ -25,6 +25,15 @@ var assert = require('assert'),
 
 var USERS_FIELDS = [ 'id', 'username', 'email', 'password', 'salt', 'createdAt', 'modifiedAt', 'resetToken', 'displayName' ].join(',');
 
+function postProcess(result) {
+    assert.strictEqual(typeof result, 'object');
+
+    // The username may be null or undefined in the db, let's ensure it is a string
+    result.username = result.username || '';
+
+    return result;
+}
+
 function get(userId, callback) {
     assert.strictEqual(typeof userId, 'string');
     assert.strictEqual(typeof callback, 'function');
@@ -33,7 +42,7 @@ function get(userId, callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -45,7 +54,7 @@ function getByUsername(username, callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -57,7 +66,7 @@ function getByEmail(email, callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -70,7 +79,7 @@ function getOwner(callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -84,7 +93,7 @@ function getByResetToken(resetToken, callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -100,6 +109,8 @@ function getAllWithGroupIds(callback) {
             result.groupIds = result.groupIds ? result.groupIds.split(',') : [ ];
         });
 
+        results.forEach(postProcess);
+
         callback(null, results);
     });
 }
@@ -107,10 +118,11 @@ function getAllWithGroupIds(callback) {
 function getAllAdmins(callback) {
     assert.strictEqual(typeof callback, 'function');
 
-    database.query('SELECT ' + USERS_FIELDS + ' FROM users, groupMembers WHERE groupMembers.groupId = ? AND users.id = groupMembers.userId',
-            [ groups.ADMIN_GROUP_ID ], function (error, results) {
+    database.query('SELECT ' + USERS_FIELDS + ' FROM users, groupMembers WHERE groupMembers.groupId = ? AND users.id = groupMembers.userId', [ groups.ADMIN_GROUP_ID ], function (error, results) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
 
+        results.forEach(postProcess);
+
         callback(null, results);
     });
 }
@@ -127,9 +139,8 @@ function add(userId, user, callback) {
     assert.strictEqual(typeof user.displayName, 'string');
     assert.strictEqual(typeof callback, 'function');
 
-    var data = [ userId, user.username, user.password, user.email, user.salt, user.createdAt, user.modifiedAt, user.resetToken, user.displayName ];
-    database.query('INSERT INTO users (id, username, password, email, salt, createdAt, modifiedAt, resetToken, displayName) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)',
-           data, function (error, result) {
+    var data = [ userId, user.username || null, user.password, user.email, user.salt, user.createdAt, user.modifiedAt, user.resetToken, user.displayName ];
+    database.query('INSERT INTO users (id, username, password, email, salt, createdAt, modifiedAt, resetToken, displayName) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)', data, function (error, result) {
         if (error && error.code === 'ER_DUP_ENTRY') return callback(new DatabaseError(DatabaseError.ALREADY_EXISTS, error));
         if (error || result.affectedRows !== 1) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
 
@@ -165,7 +176,7 @@ function getByAccessToken(accessToken, callback) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
-        callback(null, result[0]);
+        callback(null, postProcess(result[0]));
     });
 }
 
@@ -186,7 +197,12 @@ function update(userId, user, callback) {
     var fields = [ ];
     for (var k in user) {
         fields.push(k + ' = ?');
-        args.push(user[k]);
+
+        if (k === 'username') {
+            args.push(user.username || null);
+        } else {
+            args.push(user[k]);
+        }
     }
     args.push(userId);