diff --git a/src/main/java/mate/academy/service/AuthenticationService.java b/src/main/java/mate/academy/service/AuthenticationService.java
index 8f7c7c975..98254e8fd 100644
--- a/src/main/java/mate/academy/service/AuthenticationService.java
+++ b/src/main/java/mate/academy/service/AuthenticationService.java
@@ -1,16 +1,20 @@
 package mate.academy.service;
 
-public class AuthenticationService {
+import mate.academy.model.User;
+
+public class AuthenticationService extends UserService {
     /**
      * Imagine that some user wants to login to your site.
      * You should check if user credentials (login and password) are valid or not.
      * All users are stored in <code>UserService</code> class.
-     * @param email - user's email
+     *
+     * @param email    - user's email
      * @param password - user's password
      * @return true if user by email exists and passed password is equal to user's password.
      * Return false in any other cases.
      */
     public boolean login(String email, String password) {
-        return false;
+        User user = findByEmail(email);
+        return user != null && user.getPassword().equals(password);
     }
 }
diff --git a/src/main/java/mate/academy/service/UserService.java b/src/main/java/mate/academy/service/UserService.java
index 1652d7d68..94210665c 100644
--- a/src/main/java/mate/academy/service/UserService.java
+++ b/src/main/java/mate/academy/service/UserService.java
@@ -15,6 +15,11 @@ public class UserService {
      * Return <code>null</code> if there is no suitable user
      */
     public User findByEmail(String email) {
+        for (User user : users) {
+            if (user.getEmail().equals(email)) {
+                return user;
+            }
+        }
         return null;
     }
 }