diff --git a/src/routes/projectMemberInvites/create.js b/src/routes/projectMemberInvites/create.js
index 9d19f410..5187b9b9 100644
--- a/src/routes/projectMemberInvites/create.js
+++ b/src/routes/projectMemberInvites/create.js
@@ -80,7 +80,7 @@ const buildCreateInvitePromises = (req, invite, invites, data, failed) => {
   if (invite.emails) {
     // if for some emails there are already existent users, we will invite them by userId,
     // to avoid sending them registration email
-    return util.lookupUserEmails(req, invite.emails)
+    return util.lookupMultipleUserEmails(req, invite.emails, 5)
       .then((existentUsers) => {
         // existent user we will invite by userId and email
         const existentUsersWithNumberId = existentUsers.map((user) => {
diff --git a/src/routes/projectMemberInvites/create.spec.js b/src/routes/projectMemberInvites/create.spec.js
index 90ff16a7..7b958266 100644
--- a/src/routes/projectMemberInvites/create.spec.js
+++ b/src/routes/projectMemberInvites/create.spec.js
@@ -147,9 +147,9 @@ describe('Project Member Invite create', () => {
       server.services.pubsub.publish.restore();
       sinon.stub(server.services.pubsub, 'init', () => {});
       sinon.stub(server.services.pubsub, 'publish', () => {});
-      // by default mock lookupUserEmails return nothing so all the cases are not broken
+      // by default mock lookupMultipleUserEmails return nothing so all the cases are not broken
       sandbox.stub(util, 'getUserRoles', () => Promise.resolve([]));
-      sandbox.stub(util, 'lookupUserEmails', () => Promise.resolve([]));
+      sandbox.stub(util, 'lookupMultipleUserEmails', () => Promise.resolve([]));
       sandbox.stub(util, 'getMemberDetailsByUserIds', () => Promise.resolve([{
         userId: 40051333,
         firstName: 'Admin',
@@ -366,8 +366,8 @@ describe('Project Member Invite create', () => {
         }),
       });
       sandbox.stub(util, 'getHttpClient', () => mockHttpClient);
-      util.lookupUserEmails.restore();
-      sandbox.stub(util, 'lookupUserEmails', () => Promise.resolve([{
+      util.lookupMultipleUserEmails.restore();
+      sandbox.stub(util, 'lookupMultipleUserEmails', () => Promise.resolve([{
         id: '12345',
         email: 'hello@world.com',
       }]));
diff --git a/src/util.js b/src/util.js
index 46cd75b2..2f3d1109 100644
--- a/src/util.js
+++ b/src/util.js
@@ -463,6 +463,68 @@ _.assignIn(util, {
     });
   },
 
+  /**
+   * Lookup user handles from multiple emails
+   * @param {Object}  req        request
+   * @param {Array}   userEmails user emails
+   * @param {Number} maximumRequests  limit number of request on one batch
+   * @param {Boolean} isPattern  flag to indicate that pattern matching is required or not
+   * @return {Promise} promise
+   */
+  lookupMultipleUserEmails(req, userEmails, maximumRequests, isPattern = false) {
+    req.log.debug(`identityServiceEndpoint: ${config.get('identityServiceEndpoint')}`);
+
+    const httpClient = util.getHttpClient({ id: req.id, log: req.log });
+    // request generator function
+    const generateRequest = ({ token, email }) => {
+      let filter = `email=${email}`;
+      if (isPattern) {
+        filter += '&like=true';
+      }
+      return httpClient.get(`${config.get('identityServiceEndpoint')}users`, {
+        headers: {
+          Authorization: `Bearer ${token}`,
+          Accept: 'application/json',
+          'Content-Type': 'application/json',
+        },
+        params: {
+          fields: 'handle,id,email',
+          filter,
+        },
+        // set longer timeout as default 3000 could be not enough for identity service response
+        timeout: 15000,
+      });
+    };
+    // send batch of requests, one batch at one time
+    const sendBatch = (options) => {
+      const token = options.token;
+      const emails = options.emails;
+      const users = options.users || [];
+      const batch = options.batch || 0;
+      const start = batch * maximumRequests;
+      const end = (batch + 1) * maximumRequests;
+      const requests = emails.slice(start, end).map(userEmail =>
+          generateRequest({ token, email: userEmail }));
+      return Promise.all(requests)
+        .then((responses) => {
+          const data = responses.reduce((contents, response) => {
+            const content = _.get(response, 'data.result.content', []);
+            return _.concat(contents, content);
+          }, users);
+          req.log.debug(`UserHandle response batch-${batch}`, data);
+          if (end < emails.length) {
+            return sendBatch({ token, users: data, emails, batch: batch + 1 });
+          }
+          return data;
+        });
+    };
+    return util.getM2MToken()
+      .then((m2mToken) => {
+        req.log.debug(`Bearer ${m2mToken}`);
+        return sendBatch({ token: m2mToken, emails: userEmails });
+      });
+  },
+
   /**
    * Filter only members of topcoder team
    * @param {Array}  members        project members