diff --git a/fittrackee/tests/fixtures/fixtures_users.py b/fittrackee/tests/fixtures/fixtures_users.py
index e5523ad1..d80ff8fa 100644
--- a/fittrackee/tests/fixtures/fixtures_users.py
+++ b/fittrackee/tests/fixtures/fixtures_users.py
@@ -14,6 +14,14 @@ def user_1() -> User:
     return user
 
 
+@pytest.fixture()
+def user_1_upper() -> User:
+    user = User(username='TEST', email='TEST@TEST.COM', password='12345678')
+    db.session.add(user)
+    db.session.commit()
+    return user
+
+
 @pytest.fixture()
 def user_1_admin() -> User:
     admin = User(
diff --git a/fittrackee/tests/users/test_auth_api.py b/fittrackee/tests/users/test_auth_api.py
index bbf3d451..f4462463 100644
--- a/fittrackee/tests/users/test_auth_api.py
+++ b/fittrackee/tests/users/test_auth_api.py
@@ -3,6 +3,7 @@ from datetime import datetime, timedelta
 from io import BytesIO
 from unittest.mock import Mock, patch
 
+import pytest
 from flask import Flask
 from freezegun import freeze_time
 
@@ -37,8 +38,38 @@ class TestUserRegistration:
         assert response.content_type == 'application/json'
         assert response.status_code == 201
 
-    def test_it_returns_error_if_user_already_exists(
-        self, app: Flask, user_1: User
+    @pytest.mark.parametrize(
+        'input_username',
+        ['test', 'TEST'],
+    )
+    def test_it_returns_error_if_user_already_exists_with_same_username(
+        self, app: Flask, user_1: User, input_username: str
+    ) -> None:
+        client = app.test_client()
+        response = client.post(
+            '/api/auth/register',
+            data=json.dumps(
+                dict(
+                    username=input_username,
+                    email='another_email@test.com',
+                    password='12345678',
+                    password_conf='12345678',
+                )
+            ),
+            content_type='application/json',
+        )
+        data = json.loads(response.data.decode())
+        assert data['status'] == 'error'
+        assert data['message'] == 'sorry, that user already exists'
+        assert response.content_type == 'application/json'
+        assert response.status_code == 400
+
+    @pytest.mark.parametrize(
+        'input_email',
+        ['test@test.com', 'TEST@TEST.COM'],
+    )
+    def test_it_returns_error_if_user_already_exists_with_same_email(
+        self, app: Flask, user_1: User, input_email: str
     ) -> None:
         client = app.test_client()
         response = client.post(
@@ -292,12 +323,40 @@ class TestUserRegistration:
 
 
 class TestUserLogin:
-    def test_user_can_register(self, app: Flask, user_1: User) -> None:
+    @pytest.mark.parametrize(
+        'input_email',
+        ['test@test.com', 'TEST@TEST.COM'],
+    )
+    def test_user_can_login(
+        self, app: Flask, user_1: User, input_email: str
+    ) -> None:
         client = app.test_client()
 
         response = client.post(
             '/api/auth/login',
-            data=json.dumps(dict(email='test@test.com', password='12345678')),
+            data=json.dumps(dict(email=input_email, password='12345678')),
+            content_type='application/json',
+        )
+
+        assert response.content_type == 'application/json'
+        assert response.status_code == 200
+        data = json.loads(response.data.decode())
+        assert data['status'] == 'success'
+        assert data['message'] == 'successfully logged in'
+        assert data['auth_token']
+
+    @pytest.mark.parametrize(
+        'input_email',
+        ['test@test.com', 'TEST@TEST.COM'],
+    )
+    def test_user_can_login_when_user_email_is_uppercase(
+        self, app: Flask, user_1_upper: User, input_email: str
+    ) -> None:
+        client = app.test_client()
+
+        response = client.post(
+            '/api/auth/login',
+            data=json.dumps(dict(email=input_email, password='12345678')),
             content_type='application/json',
         )
 
diff --git a/fittrackee/users/auth.py b/fittrackee/users/auth.py
index 5a08ef91..33f8c3e5 100644
--- a/fittrackee/users/auth.py
+++ b/fittrackee/users/auth.py
@@ -4,7 +4,7 @@ from typing import Dict, Tuple, Union
 
 import jwt
 from flask import Blueprint, current_app, request
-from sqlalchemy import exc, or_
+from sqlalchemy import exc, func, or_
 from werkzeug.exceptions import RequestEntityTooLarge
 from werkzeug.utils import secure_filename
 
@@ -117,7 +117,10 @@ def register_user() -> Union[Tuple[Dict, int], HttpResponse]:
     try:
         # check for existing user
         user = User.query.filter(
-            or_(User.username == username, User.email == email)
+            or_(
+                func.lower(User.username) == func.lower(username),
+                func.lower(User.email) == func.lower(email),
+            )
         ).first()
         if user:
             return InvalidPayloadErrorResponse(
@@ -193,11 +196,13 @@ def login_user() -> Union[Dict, HttpResponse]:
     post_data = request.get_json()
     if not post_data:
         return InvalidPayloadErrorResponse()
-    email = post_data.get('email')
+    email = post_data.get('email', '')
     password = post_data.get('password')
     try:
         # check for existing user
-        user = User.query.filter(User.email == email).first()
+        user = User.query.filter(
+            func.lower(User.email) == func.lower(email)
+        ).first()
         if user and bcrypt.check_password_hash(user.password, password):
             # generate auth token
             auth_token = user.encode_auth_token(user.id)