diff --git a/rhodecode/model/notification.py b/rhodecode/model/notification.py
--- a/rhodecode/model/notification.py
+++ b/rhodecode/model/notification.py
@@ -332,14 +332,19 @@ class EmailNotificationModel(BaseModel):
 
         :param kwargs:
         """
+
         kwargs['rhodecode_instance_name'] = self.rhodecode_instance_name
 
         _kwargs = {
             'instance_url': h.url('home', qualified=True),
+            'whitespace_filter': self.whitespace_filter
         }
         _kwargs.update(kwargs)
         return _kwargs
 
+    def whitespace_filter(self, text):
+        return text.replace('\n', '').replace('\t', '')
+
     def get_renderer(self, type_):
         template_name = self.email_types[type_]
         return PartialRenderer(template_name)
diff --git a/rhodecode/templates/email_templates/commit_comment.mako b/rhodecode/templates/email_templates/commit_comment.mako
--- a/rhodecode/templates/email_templates/commit_comment.mako
+++ b/rhodecode/templates/email_templates/commit_comment.mako
@@ -3,7 +3,7 @@
 <%namespace name="base" file="base.mako"/>
 
 ## EMAIL SUBJECT
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 <%
 data = {
     'user': h.person(user),
diff --git a/rhodecode/templates/email_templates/email_test.mako b/rhodecode/templates/email_templates/email_test.mako
--- a/rhodecode/templates/email_templates/email_test.mako
+++ b/rhodecode/templates/email_templates/email_test.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 RhodeCode test email: ${h.format_date(date)}
 </%def>
 
diff --git a/rhodecode/templates/email_templates/main.mako b/rhodecode/templates/email_templates/main.mako
--- a/rhodecode/templates/email_templates/main.mako
+++ b/rhodecode/templates/email_templates/main.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 </%def>
 
 
diff --git a/rhodecode/templates/email_templates/password_reset.mako b/rhodecode/templates/email_templates/password_reset.mako
--- a/rhodecode/templates/email_templates/password_reset.mako
+++ b/rhodecode/templates/email_templates/password_reset.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 RhodeCode Password reset
 </%def>
 
diff --git a/rhodecode/templates/email_templates/password_reset_confirmation.mako b/rhodecode/templates/email_templates/password_reset_confirmation.mako
--- a/rhodecode/templates/email_templates/password_reset_confirmation.mako
+++ b/rhodecode/templates/email_templates/password_reset_confirmation.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 Your new RhodeCode password
 </%def>
 
diff --git a/rhodecode/templates/email_templates/pull_request_comment.mako b/rhodecode/templates/email_templates/pull_request_comment.mako
--- a/rhodecode/templates/email_templates/pull_request_comment.mako
+++ b/rhodecode/templates/email_templates/pull_request_comment.mako
@@ -3,7 +3,7 @@
 <%namespace name="base" file="base.mako"/>
 
 ## EMAIL SUBJECT
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 <%
 data = {
     'user': h.person(user),
diff --git a/rhodecode/templates/email_templates/pull_request_review.mako b/rhodecode/templates/email_templates/pull_request_review.mako
--- a/rhodecode/templates/email_templates/pull_request_review.mako
+++ b/rhodecode/templates/email_templates/pull_request_review.mako
@@ -2,7 +2,7 @@
 <%inherit file="base.mako"/>
 <%namespace name="base" file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 <%
 data = {
     'user': h.person(user),
diff --git a/rhodecode/templates/email_templates/test.mako b/rhodecode/templates/email_templates/test.mako
--- a/rhodecode/templates/email_templates/test.mako
+++ b/rhodecode/templates/email_templates/test.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 Test "Subject" ${_('hello "world"')|n}
 </%def>
 
diff --git a/rhodecode/templates/email_templates/user_registration.mako b/rhodecode/templates/email_templates/user_registration.mako
--- a/rhodecode/templates/email_templates/user_registration.mako
+++ b/rhodecode/templates/email_templates/user_registration.mako
@@ -1,7 +1,7 @@
 ## -*- coding: utf-8 -*-
 <%inherit file="base.mako"/>
 
-<%def name="subject()" filter="n,trim">
+<%def name="subject()" filter="n,trim,whitespace_filter">
 RhodeCode new user registration: ${user.username}
 </%def>
 
diff --git a/rhodecode/tests/lib/test_mako_emails.py b/rhodecode/tests/lib/test_mako_emails.py
--- a/rhodecode/tests/lib/test_mako_emails.py
+++ b/rhodecode/tests/lib/test_mako_emails.py
@@ -3,6 +3,7 @@ import collections
 import pytest
 
 from rhodecode.lib.utils import PartialRenderer
+from rhodecode.lib.utils2 import AttributeDict
 from rhodecode.model.notification import EmailNotificationModel
 
 
@@ -66,3 +67,57 @@ def test_render_pr_email(pylonsapp, user
 
     # subject
     assert subject == 'Marcin Kuzminski wants you to review pull request #200: "Example Pull Request"'
+
+
+@pytest.mark.parametrize('mention', [
+    True,
+    False
+])
+@pytest.mark.parametrize('email_type', [
+    EmailNotificationModel.TYPE_COMMIT_COMMENT,
+    EmailNotificationModel.TYPE_PULL_REQUEST_COMMENT
+])
+def test_render_comment_subject_no_newlines(pylonsapp, mention, email_type):
+    ref = collections.namedtuple('Ref',
+        'name, type')(
+        'fxies123', 'book'
+        )
+
+    pr = collections.namedtuple('PullRequest',
+        'pull_request_id, title, description, source_ref_parts, source_ref_name, target_ref_parts, target_ref_name')(
+        200, 'Example Pull Request', 'Desc of PR', ref, 'bookmark', ref, 'Branch')
+
+    source_repo = target_repo = collections.namedtuple('Repo',
+        'type, repo_name')(
+        'hg', 'pull_request_1')
+
+    kwargs = {
+        'user': '<marcin@rhodecode.com> Marcin Kuzminski',
+        'commit': AttributeDict(raw_id='a'*40, message='Commit message'),
+        'status_change': 'approved',
+        'commit_target_repo': AttributeDict(),
+        'repo_name': 'test-repo',
+        'comment_file': 'test-file.py',
+        'comment_line': 'n100',
+        'comment_type': 'note',
+        'commit_comment_url': 'http://comment-url',
+        'instance_url': 'http://rc-instance',
+        'comment_body': 'hello world',
+        'mention': mention,
+
+        'pr_comment_url': 'http://comment-url',
+        'pr_source_repo': AttributeDict(repo_name='foobar'),
+        'pr_source_repo_url': 'http://soirce-repo/url',
+        'pull_request': pr,
+        'pull_request_commits': [],
+
+        'pull_request_target_repo': target_repo,
+        'pull_request_target_repo_url': 'x',
+
+        'pull_request_source_repo': source_repo,
+        'pull_request_source_repo_url': 'x',
+    }
+    subject, headers, body, body_plaintext = EmailNotificationModel().render_email(
+        email_type, **kwargs)
+
+    assert '\n' not in subject