diff --git a/README.md b/README.md
index 1f2430f66..b756b5314 100644
--- a/README.md
+++ b/README.md
@@ -1010,7 +1010,7 @@ There are two ways to use the gRPC library in Unity:
 
 Since the maintenance of the C-core based library has ended in the gRPC project, we recommend using [YetAnotherHttpHandler](https://github.com/Cysharp/YetAnotherHttpHandler) . Please refer to the [README of YetAnotherHttpHandler](https://github.com/Cysharp/YetAnotherHttpHandler) for installation instructions.
 
-If you are using the C-core gRPC library, please define `USE_GRPC_CCORE` symbol in "Scripting Define Symbols".
+If you are using the C-core gRPC library, please define `MAGICONION_USE_GRPC_CCORE` symbol in "Scripting Define Symbols".
 
 ### Install MessagePack for C#
 MessagePack for C# is not included in MagicOnion package. You need to download and install separately.
diff --git a/samples/ChatApp/ChatApp.Unity/Assets/Scripts/InitialSettings.cs b/samples/ChatApp/ChatApp.Unity/Assets/Scripts/InitialSettings.cs
index a43526bbf..b28c00032 100644
--- a/samples/ChatApp/ChatApp.Unity/Assets/Scripts/InitialSettings.cs
+++ b/samples/ChatApp/ChatApp.Unity/Assets/Scripts/InitialSettings.cs
@@ -1,6 +1,6 @@
 using System.IO;
 using MagicOnion.Client;
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using Grpc.Core;
 #else
 using Grpc.Net.Client;
@@ -35,7 +35,7 @@ static void RegisterResolvers()
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
         public static void OnRuntimeInitialize()
         {
-#if !USE_GRPC_CCORE
+#if !MAGICONION_USE_GRPC_CCORE
             // Use Grpc.Net.Client instead of C-core gRPC library.
             GrpcChannelProviderHost.Initialize(
                 new GrpcNetClientGrpcChannelProvider(() => new GrpcChannelOptions()
@@ -46,7 +46,7 @@ public static void OnRuntimeInitialize()
                     }
                 }));
 #endif
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
             // Initialize gRPC channel provider when the application is loaded.
             GrpcChannelProviderHost.Initialize(new DefaultGrpcChannelProvider(new GrpcCCoreChannelOptions(new[]
             {
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/ChannelExtensions.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/ChannelExtensions.cs
index edb4e0e71..cc3c94601 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/ChannelExtensions.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/ChannelExtensions.cs
@@ -1,4 +1,4 @@
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using Grpc.Core;
 using System;
 using System.Collections.Generic;
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/DefaultGrpcChannelProvider.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/DefaultGrpcChannelProvider.cs
index 8a87ffa67..525c31905 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/DefaultGrpcChannelProvider.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/DefaultGrpcChannelProvider.cs
@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using Grpc.Core;
 #else
 using Grpc.Net.Client;
@@ -12,7 +12,7 @@ namespace MagicOnion.Unity
     /// <summary>
     /// Provide and manage gRPC channels for MagicOnion.
     /// </summary>
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
     public class DefaultGrpcChannelProvider : GrpcCCoreGrpcChannelProvider
     {
         public DefaultGrpcChannelProvider() : base() { }
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/Editor/GrpcChannelProviderMonitor.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/Editor/GrpcChannelProviderMonitor.cs
index 57179a3ce..8bb7a7924 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/Editor/GrpcChannelProviderMonitor.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/Editor/GrpcChannelProviderMonitor.cs
@@ -5,7 +5,7 @@
 #if MAGICONION_UNITASK_SUPPORT
 using Cysharp.Threading.Tasks;
 #endif
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using Channel = Grpc.Core.Channel;
 #else
 using Grpc.Net.Client;
@@ -73,7 +73,7 @@ public void DrawChannels()
                 {
                     using (new EditorGUILayout.HorizontalScope())
                     {
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
                         if (diagInfo.UnderlyingChannel is Channel grpcCCoreChannel)
                         {
                             EditorGUILayout.LabelField($"Channel:  {channel.Id} ({channel.Target}; State={grpcCCoreChannel.State})", EditorStyles.boldLabel);
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcCCoreGrpcChannelProvider.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcCCoreGrpcChannelProvider.cs
index 1ef749fc4..b57038c8a 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcCCoreGrpcChannelProvider.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcCCoreGrpcChannelProvider.cs
@@ -1,4 +1,4 @@
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using System;
 using System.Collections.Generic;
 using Grpc.Core;
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.CCore.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.CCore.cs
index 43da9b838..c4eb7d86b 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.CCore.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.CCore.cs
@@ -1,4 +1,4 @@
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using System.Collections.Generic;
 using Grpc.Core;
 
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.GrpcNet.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.GrpcNet.cs
index 7597409a7..fa7695b91 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.GrpcNet.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelProviderExtensions.GrpcNet.cs
@@ -1,4 +1,4 @@
-#if !USE_GRPC_CCORE
+#if !MAGICONION_USE_GRPC_CCORE
 using Grpc.Net.Client;
 
 namespace MagicOnion.Unity
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelx.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelx.cs
index 089f8098f..6f18e28b4 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelx.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcChannelx.cs
@@ -10,7 +10,7 @@
 using Cysharp.Threading.Tasks;
 #endif
 using Grpc.Core;
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
 using Channel = Grpc.Core.Channel;
 #else
 using Grpc.Net.Client;
@@ -152,7 +152,7 @@ public async Task ConnectAsync(DateTime? deadline = null)
 #endif
         {
             ThrowIfDisposed();
-#if USE_GRPC_CCORE
+#if MAGICONION_USE_GRPC_CCORE
             if (_channel is Channel grpcCChannel)
             {
                 await grpcCChannel.ConnectAsync(deadline);
diff --git a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcNetClientGrpcChannelProvider.cs b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcNetClientGrpcChannelProvider.cs
index 2def88797..b5a1a47db 100644
--- a/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcNetClientGrpcChannelProvider.cs
+++ b/src/MagicOnion.Client.Unity/Assets/Scripts/MagicOnion/MagicOnion.Unity/GrpcNetClientGrpcChannelProvider.cs
@@ -1,4 +1,4 @@
-#if !USE_GRPC_CCORE
+#if !MAGICONION_USE_GRPC_CCORE
 using System;
 using System.Collections.Generic;
 using Grpc.Net.Client;