diff --git a/src/main/java/eu/ztsh/wymiana/exception/UserAlreadyExistsException.java b/src/main/java/eu/ztsh/wymiana/exception/UserAlreadyExistsException.java
new file mode 100644
index 0000000..659b495
--- /dev/null
+++ b/src/main/java/eu/ztsh/wymiana/exception/UserAlreadyExistsException.java
@@ -0,0 +1,11 @@
+package eu.ztsh.wymiana.exception;
+
+import eu.ztsh.wymiana.web.model.UserCreateRequest;
+
+public class UserAlreadyExistsException extends RuntimeException {
+
+    public UserAlreadyExistsException(UserCreateRequest entity) {
+        super("User with PESEL %s already exists".formatted(entity.pesel()));
+    }
+
+}
diff --git a/src/main/java/eu/ztsh/wymiana/service/UserService.java b/src/main/java/eu/ztsh/wymiana/service/UserService.java
new file mode 100644
index 0000000..01cba7c
--- /dev/null
+++ b/src/main/java/eu/ztsh/wymiana/service/UserService.java
@@ -0,0 +1,31 @@
+package eu.ztsh.wymiana.service;
+
+import eu.ztsh.wymiana.data.repository.UserRepository;
+import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
+import eu.ztsh.wymiana.model.User;
+import eu.ztsh.wymiana.util.UserMapper;
+import eu.ztsh.wymiana.web.model.UserCreateRequest;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.Optional;
+
+@RequiredArgsConstructor
+@Service
+public class UserService {
+
+    private final UserRepository userRepository;
+
+    public User create(@Valid UserCreateRequest request) {
+        if (userRepository.findById(request.pesel()).isPresent()) {
+            throw new UserAlreadyExistsException(request);
+        }
+        return UserMapper.entityToPojo(userRepository.save(UserMapper.requestToEntity(request)));
+    }
+
+    public Optional<User> get(String pesel) {
+        return userRepository.findById(pesel).map(UserMapper::entityToPojo);
+    }
+
+}
diff --git a/src/main/java/eu/ztsh/wymiana/util/CurrencyMapper.java b/src/main/java/eu/ztsh/wymiana/util/CurrencyMapper.java
new file mode 100644
index 0000000..7542187
--- /dev/null
+++ b/src/main/java/eu/ztsh/wymiana/util/CurrencyMapper.java
@@ -0,0 +1,24 @@
+package eu.ztsh.wymiana.util;
+
+import eu.ztsh.wymiana.data.entity.CurrencyEntity;
+import eu.ztsh.wymiana.model.Currency;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class CurrencyMapper {
+
+    public static Currency entityToPojo(CurrencyEntity entity) {
+        return new Currency(entity.getSymbol(), entity.getAmount());
+    }
+
+    public static Map<String, Currency> entitiesToPojoMap(List<CurrencyEntity> values) {
+        return values.stream().map(CurrencyMapper::entityToPojo)
+            .collect(Collectors.toMap(Currency::symbol, pojo -> pojo));
+    }
+
+    private CurrencyMapper() {
+    }
+
+}
diff --git a/src/main/java/eu/ztsh/wymiana/util/UserMapper.java b/src/main/java/eu/ztsh/wymiana/util/UserMapper.java
new file mode 100644
index 0000000..b4aff44
--- /dev/null
+++ b/src/main/java/eu/ztsh/wymiana/util/UserMapper.java
@@ -0,0 +1,25 @@
+package eu.ztsh.wymiana.util;
+
+import eu.ztsh.wymiana.data.entity.CurrencyEntity;
+import eu.ztsh.wymiana.data.entity.UserEntity;
+import eu.ztsh.wymiana.model.User;
+import eu.ztsh.wymiana.web.model.UserCreateRequest;
+
+import java.util.List;
+
+public class UserMapper {
+
+    public static User entityToPojo(UserEntity entity) {
+        return new User(entity.getName(), entity.getSurname(), entity.getPesel(),
+            CurrencyMapper.entitiesToPojoMap(entity.getCurrencies()));
+    }
+
+    public static UserEntity requestToEntity(UserCreateRequest request) {
+        return new UserEntity(request.pesel(), request.name(), request.surname(),
+            List.of(new CurrencyEntity(request.pesel(), "PLN", request.pln())));
+    }
+
+    private UserMapper() {
+    }
+
+}
diff --git a/src/test/java/eu/ztsh/wymiana/EntityCreator.java b/src/test/java/eu/ztsh/wymiana/EntityCreator.java
index 9caa4c8..77ae953 100644
--- a/src/test/java/eu/ztsh/wymiana/EntityCreator.java
+++ b/src/test/java/eu/ztsh/wymiana/EntityCreator.java
@@ -2,6 +2,7 @@ package eu.ztsh.wymiana;
 
 import eu.ztsh.wymiana.data.entity.CurrencyEntity;
 import eu.ztsh.wymiana.data.entity.UserEntity;
+import eu.ztsh.wymiana.web.model.UserCreateRequest;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -22,6 +23,10 @@ public class EntityCreator {
         return new UserEntityBuilder();
     }
 
+    public static UserCreateRequest userRequest() {
+        return new UserCreateRequest(Constants.NAME, Constants.SURNAME, Constants.PESEL, Constants.PLN);
+    }
+
     public static class UserEntityBuilder {
 
         String name;
@@ -56,7 +61,7 @@ public class EntityCreator {
         }
 
         public UserEntity build() {
-            var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.NAME);
+            var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.PESEL);
             List<CurrencyEntity> currencies = new ArrayList<>();
             if (pln > 0) {
                 currencies.add(new CurrencyEntity(nonnulPesel, "PLN", pln));
@@ -68,9 +73,9 @@ public class EntityCreator {
                 currencies.add(new CurrencyEntity(nonnulPesel, "PLN", Constants.PLN));
             }
             return new UserEntity(
+                nonnulPesel,
                 Optional.ofNullable(name).orElse(Constants.NAME),
                 Optional.ofNullable(surname).orElse(Constants.SURNAME),
-                nonnulPesel,
                 currencies
             );
         }
diff --git a/src/test/java/eu/ztsh/wymiana/service/UserServiceTest.java b/src/test/java/eu/ztsh/wymiana/service/UserServiceTest.java
new file mode 100644
index 0000000..4a9b94b
--- /dev/null
+++ b/src/test/java/eu/ztsh/wymiana/service/UserServiceTest.java
@@ -0,0 +1,63 @@
+package eu.ztsh.wymiana.service;
+
+import eu.ztsh.wymiana.EntityCreator;
+import eu.ztsh.wymiana.RepositoryBasedTest;
+import eu.ztsh.wymiana.data.repository.UserRepository;
+import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
+import eu.ztsh.wymiana.util.UserMapper;
+import jakarta.transaction.Transactional;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class UserServiceTest extends RepositoryBasedTest {
+
+    private final UserService userService;
+
+    @Autowired
+    public UserServiceTest(UserRepository userRepository) {
+        super(userRepository);
+        userService = new UserService(userRepository);
+    }
+
+    @Test
+    @Transactional
+    void createNewUserTest() {
+        userService.create(EntityCreator.userRequest());
+        var entity = EntityCreator.user().build();
+        expect(entity);
+    }
+
+    @Test
+    void createDuplicatedUser() {
+        var first = EntityCreator.userRequest();
+        var second = EntityCreator.userRequest();
+        userService.create(first);
+        assertThatThrownBy(() -> userService.create(second))
+            .isInstanceOf(UserAlreadyExistsException.class)
+            .hasMessage("User with PESEL %s already exists".formatted(EntityCreator.Constants.PESEL));
+    }
+
+    @Test
+    @Transactional
+    void getExistingUserTest() {
+        var entity = EntityCreator.user().build();
+        userRepository.save(entity);
+        var userOptional = userService.get(EntityCreator.Constants.PESEL);
+        var expected = UserMapper.entityToPojo(entity);
+        assertThat(userOptional)
+            .isNotEmpty()
+            .get()
+            .usingRecursiveComparison()
+            .isEqualTo(expected);
+    }
+
+    @Test
+    void getNonExistingUserTest() {
+        var userOptional = userService.get(EntityCreator.Constants.PESEL);
+        assertThat(userOptional).isEmpty();
+    }
+
+}
diff --git a/src/test/java/eu/ztsh/wymiana/util/UserMapperTest.java b/src/test/java/eu/ztsh/wymiana/util/UserMapperTest.java
new file mode 100644
index 0000000..f3fc91d
--- /dev/null
+++ b/src/test/java/eu/ztsh/wymiana/util/UserMapperTest.java
@@ -0,0 +1,37 @@
+package eu.ztsh.wymiana.util;
+
+import eu.ztsh.wymiana.EntityCreator;
+import eu.ztsh.wymiana.model.Currency;
+import eu.ztsh.wymiana.model.User;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class UserMapperTest {
+
+    @Test
+    void entityToPojoTest() {
+        var entity = EntityCreator.user().build();
+        var expected = new User(
+            EntityCreator.Constants.NAME,
+            EntityCreator.Constants.SURNAME,
+            EntityCreator.Constants.PESEL,
+            Map.of("PLN", new Currency("PLN", EntityCreator.Constants.PLN))
+        );
+        assertThat(UserMapper.entityToPojo(entity))
+            .usingRecursiveComparison()
+            .isEqualTo(expected);
+    }
+
+    @Test
+    void requestToEntityTest() {
+        var request = EntityCreator.userRequest();
+        var expected = EntityCreator.user().build();
+        assertThat(UserMapper.requestToEntity(request))
+            .usingRecursiveComparison()
+            .isEqualTo(expected);
+    }
+
+}