diff --git a/pagure/api/fork.py b/pagure/api/fork.py
index ebd01f3..1ec439d 100644
--- a/pagure/api/fork.py
+++ b/pagure/api/fork.py
@@ -16,7 +16,7 @@ import pagure
 import pagure.exceptions
 import pagure.lib
 import pagure.lib.tasks
-from pagure import APP, SESSION, is_repo_committer
+from pagure import APP, SESSION, is_repo_committer, api_authenticated
 from pagure.api import (API, api_method, api_login_required, APIERROR,
                         get_authorized_api_project)
 
@@ -718,3 +718,107 @@ def api_pull_request_add_flag(repo, requestid, username=None, namespace=None):
 
     jsonout = flask.jsonify(output)
     return jsonout
+
+
+@API.route(
+    '/<repo>/pull-request/<int:requestid>/subscribe',
+    methods=['POST'])
+@API.route(
+    '/<namespace>/<repo>/pull-request/<int:requestid>/subscribe',
+    methods=['POST'])
+@API.route(
+    '/fork/<username>/<repo>/pull-request/<int:requestid>/subscribe',
+    methods=['POST'])
+@API.route(
+    '/fork/<username>/<namespace>/<repo>/pull-request/<int:requestid>/subscribe',
+    methods=['POST'])
+@api_login_required(acls=['issue_subscribe'])
+@api_method
+def api_subscribe_pull_request(repo, requestid, username=None, namespace=None):
+    """
+    Subscribe to an pull-request
+    ----------------------------
+    Allows someone to subscribe to or unsubscribe from the notifications
+    related to a pull-request.
+
+    ::
+
+        POST /api/0/<repo>/pull-request/<request id>/subscribe
+        POST /api/0/<namespace>/<repo>/pull-request/<request id>/subscribe
+
+    ::
+
+        POST /api/0/fork/<username>/<repo>/pull-request/<request id>/subscribe
+        POST /api/0/fork/<username>/<namespace>/<repo>/pull-request/<request id>/subscribe
+
+    Input
+    ^^^^^
+
+    +--------------+----------+---------------+---------------------------+
+    | Key          | Type     | Optionality   | Description               |
+    +==============+==========+===============+===========================+
+    | ``status``   | boolean  | Mandatory     | The intended subscription |
+    |              |          |               | status. ``true`` for      |
+    |              |          |               | subscribing, ``false``    |
+    |              |          |               | for unsubscribing.        |
+    +--------------+----------+---------------+---------------------------+
+
+    Sample response
+    ^^^^^^^^^^^^^^^
+
+    ::
+
+        {
+          "message": "User subscribed"
+        }
+
+    """  # noqa
+
+    repo = get_authorized_api_project(
+        SESSION, repo, user=username, namespace=namespace)
+
+    output = {}
+
+    if repo is None:
+        raise pagure.exceptions.APIError(
+            404, error_code=APIERROR.ENOPROJECT)
+
+    if not repo.settings.get('pull_requests', True):
+        raise pagure.exceptions.APIError(
+            404, error_code=APIERROR.EPULLREQUESTSDISABLED)
+
+    if api_authenticated():
+        if flask.g.token.project and repo != flask.g.token.project:
+            raise pagure.exceptions.APIError(
+                401, error_code=APIERROR.EINVALIDTOK)
+
+    request = pagure.lib.search_pull_requests(
+        SESSION, project_id=repo.id, requestid=requestid)
+
+    if not request:
+        raise pagure.exceptions.APIError(404, error_code=APIERROR.ENOREQ)
+
+    form = pagure.forms.SubscribtionForm(csrf_enabled=False)
+    if form.validate_on_submit():
+        status = str(form.status.data).strip().lower() in ['1', 'true']
+        try:
+            # Toggle subscribtion
+            message = pagure.lib.set_watch_obj(
+                SESSION,
+                user=flask.g.fas_user.username,
+                obj=request,
+                watch_status=status
+            )
+            SESSION.commit()
+            output['message'] = message
+        except SQLAlchemyError as err:  # pragma: no cover
+            SESSION.rollback()
+            APP.logger.exception(err)
+            raise pagure.exceptions.APIError(400, error_code=APIERROR.EDBERROR)
+
+    else:
+        raise pagure.exceptions.APIError(
+            400, error_code=APIERROR.EINVALIDREQ, errors=form.errors)
+
+    jsonout = flask.jsonify(output)
+    return jsonout
diff --git a/pagure/templates/pull_request.html b/pagure/templates/pull_request.html
index 7a3059b..800b175 100644
--- a/pagure/templates/pull_request.html
+++ b/pagure/templates/pull_request.html
@@ -719,7 +719,8 @@
       </div>
     </div>
 
-    {% if authenticated and subscribers %}
+    {% if authenticated %}
+      {% if subscribers %}
       <div class="card">
         <div class="card-block">
           <fieldset class="form-group">
@@ -736,6 +737,16 @@
           </fieldset>
         </div>
       </div>
+      {% endif %}
+      <div class="col-md-4 card-block">
+        <button class="btn btn-md" id="subcribe-btn"
+        {% if g.fas_user.username in subscribers -%}
+          title="Unsubscribe from this pull-request">Unsubscribe
+        {%- else -%}
+          title="Subscribe to this pull-request">Subscribe
+        {%- endif -%}
+        </button>
+      </div>
     {% endif %}
 
     </section>
@@ -1286,6 +1297,41 @@ function updateHighlight(onload) {
 }
 
 $(document).ready(function () {
+  {% if authenticated and pull_request %}
+  function set_up_subcribed() {
+    $("#subcribe-btn").click(function(){
+      var _url = "{{ url_for(
+        'api_ns.api_subscribe_pull_request',
+        repo=repo.name,
+        username=username,
+        namespace=repo.namespace,
+        requestid=pull_request.id
+        ) }}";
+      var _btn = $("#subcribe-btn");
+      var _data = {};
+      if (_btn.text() == 'Unsubscribe'){
+        _data.status = false;
+      } else {
+        _data.status = true;
+      }
+      console.log(_data);
+      $.post( _url, _data ).done(
+        function(data) {
+          var _btn = $("#subcribe-btn");
+          if (_btn.text() == 'Subscribe'){
+            _btn.text('Unsubscribe');
+          } else {
+            _btn.text('Subscribe');
+          }
+          return false;
+        }
+      )
+      return false;
+    });
+  };
+  set_up_subcribed();
+  {% endif %}
+
   updateHighlight(true)
  {% if form %}
   $( "#previewinmarkdown" ).click(
diff --git a/tests/test_pagure_flask_api_fork.py b/tests/test_pagure_flask_api_fork.py
index 5cf42ca..4d13c7e 100644
--- a/tests/test_pagure_flask_api_fork.py
+++ b/tests/test_pagure_flask_api_fork.py
@@ -1249,6 +1249,173 @@ class PagureFlaskApiForktests(tests.Modeltests):
         self.assertEqual(request.flags[0].comment, 'Tests passed')
         self.assertEqual(request.flags[0].percent, 100)
 
+    @patch('pagure.lib.git.update_git')
+    @patch('pagure.lib.notify.send_email')
+    def test_api_subscribe_pull_request(self, p_send_email, p_ugt):
+        """ Test the api_subscribe_pull_request method of the flask api. """
+        p_send_email.return_value = True
+        p_ugt.return_value = True
+
+        item = pagure.lib.model.User(
+            user='bar',
+            fullname='bar foo',
+            password='foo',
+            default_email='bar@bar.com',
+        )
+        self.session.add(item)
+        item = pagure.lib.model.UserEmail(
+            user_id=3,
+            email='bar@bar.com')
+        self.session.add(item)
+
+        self.session.commit()
+
+        tests.create_projects(self.session)
+        tests.create_tokens(self.session, user_id=3)
+        tests.create_tokens_acl(self.session)
+
+        headers = {'Authorization': 'token aaabbbcccddd'}
+
+        # Invalid project
+        output = self.app.post(
+            '/api/0/foo/pull-request/1/subscribe', headers=headers)
+        self.assertEqual(output.status_code, 404)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {
+              "error": "Project not found",
+              "error_code": "ENOPROJECT",
+            }
+        )
+
+        # Valid token, wrong project
+        output = self.app.post(
+            '/api/0/test2/pull-request/1/subscribe', headers=headers)
+        self.assertEqual(output.status_code, 401)
+        data = json.loads(output.data)
+        self.assertEqual(pagure.api.APIERROR.EINVALIDTOK.name,
+                         data['error_code'])
+        self.assertEqual(pagure.api.APIERROR.EINVALIDTOK.value, data['error'])
+
+        # No input
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe', headers=headers)
+        self.assertEqual(output.status_code, 404)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {
+                u'error': u'Pull-Request not found',
+                u'error_code': u'ENOREQ'
+            }
+        )
+
+        # Create pull-request
+        repo = pagure.get_authorized_project(self.session, 'test')
+        req = pagure.lib.new_pull_request(
+            session=self.session,
+            repo_from=repo,
+            branch_from='feature',
+            repo_to=repo,
+            branch_to='master',
+            title='test pull-request',
+            user='pingou',
+            requestfolder=None,
+        )
+        self.session.commit()
+        self.assertEqual(req.id, 1)
+        self.assertEqual(req.title, 'test pull-request')
+
+        # Check subscribtion before
+        repo = pagure.get_authorized_project(self.session, 'test')
+        request = pagure.lib.search_pull_requests(
+            self.session, project_id=1, requestid=1)
+        self.assertEqual(
+            pagure.lib.get_watch_list(self.session, request),
+            set(['pingou']))
+
+        # Unsubscribe - no changes
+        data = {}
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe',
+            data=data, headers=headers)
+        self.assertEqual(output.status_code, 200)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {'message': 'You are no longer watching this pull-request'}
+        )
+
+        data = {}
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe',
+            data=data, headers=headers)
+        self.assertEqual(output.status_code, 200)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {'message': 'You are no longer watching this pull-request'}
+        )
+
+        # No change
+        repo = pagure.get_authorized_project(self.session, 'test')
+        request = pagure.lib.search_pull_requests(
+            self.session, project_id=1, requestid=1)
+        self.assertEqual(
+            pagure.lib.get_watch_list(self.session, request),
+            set(['pingou']))
+
+        # Subscribe
+        data = {'status': True}
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe',
+            data=data, headers=headers)
+        self.assertEqual(output.status_code, 200)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {'message': 'You are now watching this pull-request'}
+        )
+
+        # Subscribe - no changes
+        data = {'status': True}
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe',
+            data=data, headers=headers)
+        self.assertEqual(output.status_code, 200)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {'message': 'You are now watching this pull-request'}
+        )
+
+        repo = pagure.get_authorized_project(self.session, 'test')
+        request = pagure.lib.search_pull_requests(
+            self.session, project_id=1, requestid=1)
+        self.assertEqual(
+            pagure.lib.get_watch_list(self.session, request),
+            set(['pingou', 'bar']))
+
+        # Unsubscribe
+        data = {}
+        output = self.app.post(
+            '/api/0/test/pull-request/1/subscribe',
+            data=data, headers=headers)
+        self.assertEqual(output.status_code, 200)
+        data = json.loads(output.data)
+        self.assertDictEqual(
+            data,
+            {'message': 'You are no longer watching this pull-request'}
+        )
+
+        repo = pagure.get_authorized_project(self.session, 'test')
+        request = pagure.lib.search_pull_requests(
+            self.session, project_id=1, requestid=1)
+        self.assertEqual(
+            pagure.lib.get_watch_list(self.session, request),
+            set(['pingou']))
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)