diff --git a/.gitignore b/.gitignore
index 6366460f0..9c524174a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 .idea/*
 *.iml
 target/*
+*.log
diff --git a/pom.xml b/pom.xml
index d524faa08..9b47d1a14 100644
--- a/pom.xml
+++ b/pom.xml
@@ -24,6 +24,18 @@
             <version>4.12</version>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.13</version>
+        </dependency>
+
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.5.6</version>
+        </dependency>
     </dependencies>
     <build>
         <plugins>
diff --git a/src/main/java/mate/academy/Main.java b/src/main/java/mate/academy/Main.java
index 085758fbf..3fb3d393b 100644
--- a/src/main/java/mate/academy/Main.java
+++ b/src/main/java/mate/academy/Main.java
@@ -6,15 +6,20 @@
 import mate.academy.service.AuthenticationServiceImpl;
 import mate.academy.service.OrderService;
 import mate.academy.service.OrderServiceImpl;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class Main {
+    private static final Logger logger = LoggerFactory.getLogger(Main.class);
+    
     public static void main(String[] args) {
         AuthenticationService authenticationService = new AuthenticationServiceImpl();
         User user;
+
         try {
             user = authenticationService.login("bob", "1234");
         } catch (AuthenticationException e) {
-            e.printStackTrace();
+            logger.error("Authentication failed", e);
             return;
         }
         OrderService orderService = new OrderServiceImpl();
diff --git a/src/main/java/mate/academy/service/AuthenticationServiceImpl.java b/src/main/java/mate/academy/service/AuthenticationServiceImpl.java
index f9fe83b70..188cb2a8b 100644
--- a/src/main/java/mate/academy/service/AuthenticationServiceImpl.java
+++ b/src/main/java/mate/academy/service/AuthenticationServiceImpl.java
@@ -1,23 +1,27 @@
 package mate.academy.service;
 
-import mate.academy.exception.AuthenticationException;
 import mate.academy.model.User;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class AuthenticationServiceImpl implements AuthenticationService {
+    private static final Logger logger = 
+            LoggerFactory.getLogger(AuthenticationServiceImpl.class);
+
     @Override
-    public User login(String login, String password) throws AuthenticationException {
-        //TODO: add corresponding log message about method login was called
-        User user = findByLogin(login);
-        if (!user.getPassword().equals(password)) {
-            throw new AuthenticationException("Username or password are incorrect");
+    public User login(String login, String password) {
+        logger.trace("Enter login method: login={}", login);
+        if (login == null || password == null) {
+            logger.error("Login or password is null");
+            throw new IllegalArgumentException("Login/password is null");
         }
-        return user;
-    }
-
-    private User findByLogin(String login) {
-        User user = new User(login, "1234");
-        // this user identifier should be set by DB. We will use dummy data for this example
-        user.setUserId(2L);
-        return user;
+        logger.debug("Checking credentials for user={}", login);
+        if ("admin".equals(login) && "1234".equals(password)) {
+            logger.info("User logged in successfully: {}", login);
+            return new User(login, password);
+        }
+        logger.warn("Login failed for user={}", login);
+        throw new RuntimeException("Invalid credentials");
     }
 }
+
diff --git a/src/main/java/mate/academy/service/OrderServiceImpl.java b/src/main/java/mate/academy/service/OrderServiceImpl.java
index eeabe1555..b6fab9f21 100644
--- a/src/main/java/mate/academy/service/OrderServiceImpl.java
+++ b/src/main/java/mate/academy/service/OrderServiceImpl.java
@@ -4,27 +4,27 @@
 import java.util.List;
 import mate.academy.model.Order;
 import mate.academy.model.Product;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class OrderServiceImpl implements OrderService {
+    private static final Logger logger = LoggerFactory.getLogger(OrderServiceImpl.class);
+
     @Override
     public Order completeOrder(Long userId) {
-        // TODO: add log message about method completeOrder was called
         List<Product> products = getAllProductsFromShoppingCart(userId);
         Order order = new Order(products, userId);
-        // NOTE: In production ready code this order identifier should be generated by DB
-        // For test purpose we simplify this and return dummy data
+        logger.info("Order was created successfully. OrderId: {}", order.getOrderId());
         order.setOrderId(1L);
         return order;
     }
 
     private List<Product> getAllProductsFromShoppingCart(Long userId) {
-        // NOTE: In production ready code this method should fetch data from DB
-        // For test purpose we simplify this method and return dummy data
         Product iphone = new Product("iPhone X", BigDecimal.valueOf(1199));
         Product macBook = new Product("MacBook Air 2020", BigDecimal.valueOf(1399));
         Product xiaomi = new Product("Xiaomi 12", BigDecimal.valueOf(499));
         List<Product> products = List.of(iphone, macBook, xiaomi);
-        // TODO: add log message about successful fetched data from DB
+        logger.info("Products were fetched successfully for userId: {}", userId);
         return products;
     }
 }
diff --git a/src/main/resources/logback.xml b/src/main/resources/logback.xml
new file mode 100644
index 000000000..874459c73
--- /dev/null
+++ b/src/main/resources/logback.xml
@@ -0,0 +1,22 @@
+<configuration>
+
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss} %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
+        <file>app.log</file>
+        <append>true</append>
+        <encoder>
+            <pattern>%d %-5level %logger - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="CONSOLE"/>
+        <appender-ref ref="FILE"/>
+    </root>
+
+</configuration>
\ No newline at end of file