diff --git a/app/auth/__init__.py b/app/auth/__init__.py
index 9b71fb62..09f95d4d 100644
--- a/app/auth/__init__.py
+++ b/app/auth/__init__.py
@@ -5,6 +5,7 @@
 auth_bp = Blueprint('auth_bp', __name__, url_prefix='/api/v1/auth')
 auth_api = Api(auth_bp)
 
+from . import external_users_connection
 from . import external_users_registration
 from . import login
 from . import password_reset_confirm
@@ -15,6 +16,8 @@
 from . import token_checker
 
 
+auth_api.add_resource(external_users_connection.ExternalUserConnection,
+                      '/external_user_connection/')
 auth_api.add_resource(external_users_registration.ExternalUserRegistration,
                       '/external_user_registration/')
 auth_api.add_resource(login.Login, '/login/')
diff --git a/app/auth/external_users_connection.py b/app/auth/external_users_connection.py
new file mode 100644
index 00000000..0c0fe61a
--- /dev/null
+++ b/app/auth/external_users_connection.py
@@ -0,0 +1,90 @@
+from flask import jsonify, make_response
+from flask_apispec import doc, use_kwargs
+from flask_apispec.views import MethodResource
+from flask_jwt_extended import jwt_required
+from flask_restful import Resource
+from marshmallow import Schema, fields
+from sqlalchemy.exc import SQLAlchemyError
+
+from app import config
+from app.database import db_session
+from app.logger import app_logger as logger
+from app.models import User
+
+
+class UserConnectionSchema(Schema):
+    telegram_id = fields.Integer(required=True)
+    external_id = fields.Integer(required=True)
+
+
+class ExternalUserConnection(Resource, MethodResource):
+
+    @doc(description='Set external_id to user by his telegram_id.'
+                     'Requires "telegram_id" and "external_id" parameters.',
+         summary='Set external_id to user',
+         tags=['User Registration'],
+         responses={
+             200: {'description': 'external_id has been assigned to the user'},
+             400: {'description': 'The telegram_id can not be empty'},
+         },
+         params={
+             'telegram_id': {
+                 'description': (
+                    'Set external_id to a user with that telegram id'
+                  ),
+                 'in': 'query',
+                 'type': 'integer',
+                 'required': True
+             },
+             'external_id': {
+                 'description': (
+                    'Set that external_id to user.'
+                  ),
+                 'in': 'query',
+                 'type': 'integer',
+                 'required': True
+             },
+             'Authorization': config.PARAM_HEADER_AUTH,
+         }
+         )
+    @use_kwargs(UserConnectionSchema)
+    @jwt_required()
+    def post(self, **kwargs):
+        telegram_id = kwargs.get('telegram_id')
+        external_id = kwargs.get('external_id')
+
+        if not external_id or not telegram_id:
+            logger.info(
+                'Messages: The <telegram_id> and <external_id>  '
+                'parameters have not been passed'
+                )
+            return make_response(
+                jsonify(
+                    result=(
+                        'Необходимо указать параметры '
+                        '<telegram_id> and <external_id>.'
+                    )
+                ), 400
+                )
+
+        try:
+            user = User.query.filter_by(telegram_id=telegram_id).first()
+            user.external_id = external_id
+            db_session.commit()
+        except SQLAlchemyError as ex:
+            logger.error(f'Messages: Database commit error "{str(ex)}"')
+            db_session.rollback()
+            return make_response(
+                jsonify(message=f'Bad request: {str(ex)}'), 400
+            )
+
+        logger.info(
+            f'External user registration: The user with "{telegram_id}" '
+            f'was successfully assigned the external_id "{external_id}".'
+        )
+
+        return make_response(
+            jsonify(
+                result="Пользователю успешно присвоен external_id."
+            ), 200
+        )
diff --git a/app/auth/swagger_auth.py b/app/auth/swagger_auth.py
index 71124091..0f6aafdd 100644
--- a/app/auth/swagger_auth.py
+++ b/app/auth/swagger_auth.py
@@ -3,6 +3,7 @@
 from app.auth.login import Login
 from app.auth.password_reset import PasswordReset
 from app.auth.registration import UserRegister
+from app.auth.external_users_connection import ExternalUserConnection
 from app.auth.external_users_registration import ExternalUserRegistration
 from app.auth.token_checker import TokenChecker
 from app.auth.send_registration_invite import SendRegistrationInvite
@@ -13,6 +14,7 @@
 docs.register(UserRegister, blueprint='auth_bp')
 docs.register(PasswordReset, blueprint='auth_bp')
 docs.register(PasswordResetConfirm, blueprint='auth_bp')
+docs.register(ExternalUserConnection, blueprint='auth_bp')
 docs.register(ExternalUserRegistration, blueprint='auth_bp')
 docs.register(SendRegistrationInvite, blueprint='auth_bp')
 docs.register(TokenChecker, blueprint='auth_bp')