diff --git a/Consul.Test/AgentTest.cs b/Consul.Test/AgentTest.cs
index e31e25a87..441d8146e 100644
--- a/Consul.Test/AgentTest.cs
+++ b/Consul.Test/AgentTest.cs
@@ -709,5 +709,89 @@ public async Task Agent_Register_UseAliasCheck()
             Assert.Equal(HealthStatus.Passing, checks.Response[check2Id].Status);
             Assert.Equal("All checks passing.", checks.Response[check2Id].Output);
         }
+
+        [Fact]
+        public async Task Agent_Service_Register_With_Connect()
+        {
+            // Arrange
+            var destinationServiceID = KVTest.GenerateTestKeyName();
+            var destinationServiceRegistrationParameters = new AgentServiceRegistration
+            {
+                ID = destinationServiceID,
+                Name = destinationServiceID,
+                Port = 8000,
+                Check = new AgentServiceCheck
+                {
+                    TTL = TimeSpan.FromSeconds(15)
+                },
+                Connect = new AgentServiceConnect
+                {
+                    SidecarService = new AgentServiceRegistration
+                    {
+                        Port = 8001
+                    }
+                }
+            };
+
+            var sourceServiceID = KVTest.GenerateTestKeyName();
+            var sourceServiceRegistrationParameters = new AgentServiceRegistration
+            {
+                ID = sourceServiceID,
+                Name = sourceServiceID,
+                Port = 9000,
+                Check = new AgentServiceCheck
+                {
+                    TTL = TimeSpan.FromSeconds(15)
+                },
+                Tags = new string[] { "tag1", "tag2" },
+                Connect = new AgentServiceConnect
+                {
+                    SidecarService = new AgentServiceRegistration
+                    {
+                        Port = 9001,
+                        Proxy = new AgentServiceProxy
+                        {
+                            Upstreams = new AgentServiceProxyUpstream[] { new AgentServiceProxyUpstream { DestinationName = destinationServiceID, LocalBindPort = 9002 } }
+                        }
+                    }
+                }
+            };
+
+            // Act
+            await _client.Agent.ServiceRegister(destinationServiceRegistrationParameters);
+            await _client.Agent.ServiceRegister(sourceServiceRegistrationParameters);
+
+            // Assert
+            var services = await _client.Agent.Services();
+
+            // Assert SourceService
+            var sourceProxyServiceID = $"{sourceServiceID}-sidecar-proxy";
+            Assert.Contains(sourceServiceID, services.Response.Keys);
+            Assert.Contains(sourceProxyServiceID, services.Response.Keys);
+            AgentService sourceProxyService = services.Response[sourceProxyServiceID];
+            Assert.Equal(sourceServiceRegistrationParameters.Tags, sourceProxyService.Tags);
+            Assert.Equal(sourceServiceRegistrationParameters.Connect.SidecarService.Port, sourceProxyService.Port);
+            Assert.Equal(sourceServiceID, sourceProxyService.Proxy.DestinationServiceName);
+            Assert.Equal(sourceServiceID, sourceProxyService.Proxy.DestinationServiceID);
+            Assert.Equal("127.0.0.1", sourceProxyService.Proxy.LocalServiceAddress);
+            Assert.Equal(sourceServiceRegistrationParameters.Port, sourceProxyService.Proxy.LocalServicePort);
+            Assert.Equal(ServiceKind.ConnectProxy, sourceProxyService.Kind);
+            Assert.Single(sourceProxyService.Proxy.Upstreams);
+            Assert.Equal(sourceServiceRegistrationParameters.Connect.SidecarService.Proxy.Upstreams[0].DestinationName, sourceProxyService.Proxy.Upstreams[0].DestinationName);
+            Assert.Equal(sourceServiceRegistrationParameters.Connect.SidecarService.Proxy.Upstreams[0].LocalBindPort, sourceProxyService.Proxy.Upstreams[0].LocalBindPort);
+
+            // Assert DestinationService
+            var destinationProxyServiceID = $"{destinationServiceID}-sidecar-proxy";
+            Assert.Contains(destinationServiceID, services.Response.Keys);
+            Assert.Contains(destinationProxyServiceID, services.Response.Keys);
+            AgentService destinationProxyService = services.Response[destinationProxyServiceID];
+            Assert.Equal(destinationServiceRegistrationParameters.Connect.SidecarService.Port, destinationProxyService.Port);
+            Assert.Equal(destinationServiceID, destinationProxyService.Proxy.DestinationServiceName);
+            Assert.Equal(destinationServiceID, destinationProxyService.Proxy.DestinationServiceID);
+            Assert.Equal("127.0.0.1", destinationProxyService.Proxy.LocalServiceAddress);
+            Assert.Equal(destinationServiceRegistrationParameters.Port, destinationProxyService.Proxy.LocalServicePort);
+            Assert.Null(destinationProxyService.Proxy.Upstreams);
+            Assert.Equal(ServiceKind.ConnectProxy, destinationProxyService.Kind);
+        }
     }
 }
diff --git a/Consul.Test/ServiceKindUnitTests.cs b/Consul.Test/ServiceKindUnitTests.cs
new file mode 100644
index 000000000..d8ef63cbe
--- /dev/null
+++ b/Consul.Test/ServiceKindUnitTests.cs
@@ -0,0 +1,62 @@
+// -----------------------------------------------------------------------
+//  <copyright file="ServiceKindUnitTests.cs" company="G-Research Limited">
+//    Copyright 2020 G-Research Limited
+//
+//    Licensed under the Apache License, Version 2.0 (the "License"),
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using System.Collections.Generic;
+using Xunit;
+
+namespace Consul.Test
+{
+    public class ServiceKindUnitTests
+    {
+        public static IList<object[]> TryParseTestCases => new List<object[]>
+        {
+            new object[] { null, true, null },
+            new object[] { "", true, null },
+            new object[] { " ", true, null },
+            new object[] { "    ", true, null },
+            new object[] { "invalidvalud", false, null },
+            new object[] { "connect-proxy", true, ServiceKind.ConnectProxy },
+            new object[] { "Connect-proxy", true, ServiceKind.ConnectProxy },
+            new object[] { "mesh-gateway", true, ServiceKind.MeshGateway },
+            new object[] { "Mesh-gateway", true, ServiceKind.MeshGateway },
+            new object[] { "terminating-gateway", true, ServiceKind.TerminatingGateway },
+            new object[] { "Terminating-gateway", true, ServiceKind.TerminatingGateway },
+            new object[] { "ingress-gateway", true, ServiceKind.IngressGateway },
+            new object[] { "Ingress-gateway", true, ServiceKind.IngressGateway },
+        };
+
+        [Fact]
+        public void Test_Equals()
+        {
+            Assert.Equal(ServiceKind.IngressGateway, ServiceKind.IngressGateway);
+            Assert.Equal(ServiceKind.IngressGateway, (object)"ingress-gateway");
+            Assert.NotEqual(ServiceKind.IngressGateway, ServiceKind.ConnectProxy);
+            Assert.NotEqual(ServiceKind.IngressGateway, (object)"connect-proxy");
+        }
+
+        [Theory]
+        [MemberData(nameof(TryParseTestCases))]
+        public void TryParse(string value, bool expectedPredicateResult, ServiceKind expected)
+        {
+            bool actualPredicateResult = ServiceKind.TryParse(value, out ServiceKind actual);
+
+            Assert.Equal(expectedPredicateResult, actualPredicateResult);
+            Assert.Equal(expected, actual);
+        }
+    }
+}
diff --git a/Consul/Agent.cs b/Consul/Agent.cs
index fc8a58e31..7877d6e22 100644
--- a/Consul/Agent.cs
+++ b/Consul/Agent.cs
@@ -20,6 +20,8 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.ComponentModel;
+using System.Globalization;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -139,6 +141,64 @@ public class AgentService
         public IDictionary<string, ServiceTaggedAddress> TaggedAddresses { get; set; }
         public bool EnableTagOverride { get; set; }
         public IDictionary<string, string> Meta { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)] // If the Proxy property is serialized to have null value, a protocol error occurs when registering the service through the catalog (catalog/register) during an http request.
+        public AgentServiceProxy Proxy { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public ServiceKind Kind { get; set; }
+    }
+
+    /// <summary>
+    /// ServiceKind specifies the type of service.
+    /// </summary>
+    [TypeConverter(typeof(ServiceKindTypeConverter))]
+    public class ServiceKind : IEquatable<ServiceKind>
+    {
+        static IReadOnlyDictionary<string, ServiceKind> Map { get; } = new Dictionary<string, ServiceKind>(StringComparer.OrdinalIgnoreCase)
+        {
+            { "connect-proxy", new ServiceKind("connect-proxy") },
+            { "mesh-gateway", new ServiceKind("mesh-gateway") },
+            { "terminating-gateway", new ServiceKind("terminating-gateway") },
+            { "ingress-gateway", new ServiceKind("ingress-gateway") },
+        };
+
+        public static ServiceKind ConnectProxy => Map["connect-proxy"];
+        public static ServiceKind MeshGateway => Map["mesh-gateway"];
+        public static ServiceKind TerminatingGateway => Map["terminating-gateway"];
+        public static ServiceKind IngressGateway => Map["ingress-gateway"];
+
+        string Value { get; }
+
+        ServiceKind(string value) => Value = value;
+
+        public override bool Equals(object obj) => obj is ServiceKind typedObject ? Equals(typedObject) : Value.Equals(obj.ToString(), StringComparison.OrdinalIgnoreCase);
+
+        public bool Equals(ServiceKind other) => ReferenceEquals(this, other);
+
+        public override int GetHashCode() => Value.GetHashCode();
+
+        public override string ToString() => Value.ToString();
+
+        public static bool TryParse(string value, out ServiceKind result)
+        {
+            result = null;
+
+            if (string.IsNullOrWhiteSpace(value))
+            {
+                return true;
+            }
+
+            return Map.TryGetValue(value, out result);
+        }
+    }
+
+    class ServiceKindTypeConverter : TypeConverter
+    {
+        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) => sourceType == typeof(string);
+        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) => destinationType == typeof(string);
+        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) => ServiceKind.TryParse(value?.ToString(), out ServiceKind result) ? result : throw new NotSupportedException();
+        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) => value is null ? string.Empty : value.ToString();
     }
 
     /// <summary>
@@ -198,6 +258,12 @@ public class AgentServiceRegistration
 
         [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public IDictionary<string, ServiceTaggedAddress> TaggedAddresses { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public AgentServiceConnect Connect { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public AgentServiceProxy Proxy { get; set; }
     }
 
     /// <summary>
@@ -209,6 +275,48 @@ public class AgentCheckRegistration : AgentServiceCheck
         public string ServiceID { get; set; }
     }
 
+    /// <summary>
+    /// AgentServiceConnect specifies the configuration for Connect
+    /// </summary>
+    public class AgentServiceConnect
+    {
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public AgentServiceRegistration SidecarService { get; set; }
+    }
+
+    /// <summary>
+    /// AgentServiceProxy specifies the configuration for a Connect service proxy instance. This is only valid if Kind defines a proxy or gateway.
+    /// </summary>
+    public class AgentServiceProxy
+    {
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public string DestinationServiceID { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public int LocalServicePort { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public string LocalServiceAddress { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public string DestinationServiceName { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public AgentServiceProxyUpstream[] Upstreams { get; set; }
+    }
+
+    /// <summary>
+    /// AgentServiceProxyUpstream specifies the upstream service for which the proxy should create a listener.
+    /// </summary>
+    public class AgentServiceProxyUpstream
+    {
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public string DestinationName { get; set; }
+
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        public int LocalBindPort { get; set; }
+    }
+
     /// <summary>
     /// AgentServiceCheck is used to create an associated check for a service
     /// </summary>