diff --git a/eventhub/src/EventHub.Application.Contracts/Events/Registrations/IEventRegistrationAppService.cs b/eventhub/src/EventHub.Application.Contracts/Events/Registrations/IEventRegistrationAppService.cs
new file mode 100644
index 0000000..0aa6920
--- /dev/null
+++ b/eventhub/src/EventHub.Application.Contracts/Events/Registrations/IEventRegistrationAppService.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Threading.Tasks;
+using Volo.Abp.Application.Services;
+
+namespace EventHub.Events.Registrations
+{
+    public interface IEventRegistrationAppService : IApplicationService
+    {
+        Task RegisterAsync(Guid id);
+
+        Task UnregisterAsync(Guid id);
+    }
+}
diff --git a/eventhub/src/EventHub.Application/Events/Registrations/EventRegistrationAppService.cs b/eventhub/src/EventHub.Application/Events/Registrations/EventRegistrationAppService.cs
new file mode 100644
index 0000000..f5f81b4
--- /dev/null
+++ b/eventhub/src/EventHub.Application/Events/Registrations/EventRegistrationAppService.cs
@@ -0,0 +1,44 @@
+using System;
+using System.Threading.Tasks;
+using EventHub.Users;
+using Microsoft.AspNetCore.Authorization;
+using Volo.Abp.Domain.Repositories;
+using Volo.Abp.Users;
+
+namespace EventHub.Events.Registrations
+{
+    public class EventRegistrationAppService : EventHubAppService, IEventRegistrationAppService
+    {
+        private readonly EventRegistrationManager _eventRegistrationManager;
+        private readonly IRepository<AppUser, Guid> _userRepository;
+        private readonly IRepository<Event, Guid> _eventRepository;
+
+        public EventRegistrationAppService(
+            EventRegistrationManager eventRegistrationManager,
+            IRepository<AppUser, Guid> userRepository,
+            IRepository<Event, Guid> eventRepository)
+        {
+            _eventRegistrationManager = eventRegistrationManager;
+            _userRepository = userRepository;
+            _eventRepository = eventRepository;
+        }
+
+        [Authorize]
+        public async Task RegisterAsync(Guid id)
+        {
+            await _eventRegistrationManager.RegisterAsync(
+                await _eventRepository.GetAsync(id),
+                await _userRepository.GetAsync(CurrentUser.GetId())
+            );
+        }
+
+        [Authorize]
+        public async Task UnregisterAsync(Guid id)
+        {
+            await _eventRegistrationManager.UnregisterAsync(
+                await _eventRepository.GetAsync(id),
+                await _userRepository.GetAsync(CurrentUser.GetId())
+            );
+        }
+    }
+}
diff --git a/eventhub/src/EventHub.Domain/Properties/AssemblyInfo.cs b/eventhub/src/EventHub.Domain/Properties/AssemblyInfo.cs
index 025db80..be9bcfe 100644
--- a/eventhub/src/EventHub.Domain/Properties/AssemblyInfo.cs
+++ b/eventhub/src/EventHub.Domain/Properties/AssemblyInfo.cs
@@ -1,3 +1,4 @@
 using System.Runtime.CompilerServices;
+[assembly:InternalsVisibleToAttribute("EventHub.Application.Tests")]
 [assembly:InternalsVisibleToAttribute("EventHub.Domain.Tests")]
 [assembly:InternalsVisibleToAttribute("EventHub.TestBase")]
diff --git a/eventhub/test/EventHub.Application.Tests/Events/Registrations/EventRegistrationAppServiceTests.cs b/eventhub/test/EventHub.Application.Tests/Events/Registrations/EventRegistrationAppServiceTests.cs
new file mode 100644
index 0000000..d445dca
--- /dev/null
+++ b/eventhub/test/EventHub.Application.Tests/Events/Registrations/EventRegistrationAppServiceTests.cs
@@ -0,0 +1,72 @@
+using System;
+using System.Threading.Tasks;
+using Shouldly;
+using Volo.Abp.Domain.Repositories;
+using Volo.Abp.Users;
+using Xunit;
+
+namespace EventHub.Events.Registrations
+{
+    public class EventRegistrationAppServiceTests : EventHubApplicationTestBase
+    {
+        private readonly IEventRegistrationAppService _eventRegistrationAppService;
+        private readonly IRepository<EventRegistration, Guid> _eventRegistrationRepository;
+        private readonly EventHubTestData _testData;
+        private readonly ICurrentUser _currentUser;
+
+        public EventRegistrationAppServiceTests()
+        {
+            _eventRegistrationAppService = GetRequiredService<IEventRegistrationAppService>();
+            _eventRegistrationRepository = GetRequiredService<IRepository<EventRegistration, Guid>>();
+            _testData = GetRequiredService<EventHubTestData>();
+            _currentUser = GetRequiredService<ICurrentUser>();
+        }
+
+        [Fact]
+        public async Task Should_Register_To_An_Event()
+        {
+            await _eventRegistrationAppService.RegisterAsync(
+                _testData.AbpMicroservicesFutureEventId
+            );
+
+            (await GetRegistrationOrNull(
+                _testData.AbpMicroservicesFutureEventId,
+                _currentUser.GetId()
+            )).ShouldNotBeNull();
+        }
+
+        [Fact]
+        public async Task Should_Unregister_From_An_Event()
+        {
+            await WithUnitOfWorkAsync(async () =>
+            {
+                await _eventRegistrationRepository.InsertAsync(
+                    new EventRegistration(
+                        Guid.NewGuid(),
+                        _testData.AbpMicroservicesFutureEventId,
+                        _currentUser.GetId()
+                    )
+                );
+            });
+
+            await _eventRegistrationAppService.UnregisterAsync(
+                _testData.AbpMicroservicesFutureEventId
+            );
+
+            (await GetRegistrationOrNull(
+                _testData.AbpMicroservicesFutureEventId,
+                _currentUser.GetId())
+            ).ShouldBeNull();
+        }
+
+        private async Task<EventRegistration> GetRegistrationOrNull(Guid eventId, Guid userId)
+        {
+            return await WithUnitOfWorkAsync(async () =>
+            {
+                return await _eventRegistrationRepository.FirstOrDefaultAsync(
+                    x => x.EventId == eventId && x.UserId == userId
+                );
+            });
+        }
+    }
+}