diff --git a/src/Microsoft.AspNetCore.Antiforgery/AntiforgeryOptions.cs b/src/Microsoft.AspNetCore.Antiforgery/AntiforgeryOptions.cs
index e59b6aecd9..2c05e1dc1c 100644
--- a/src/Microsoft.AspNetCore.Antiforgery/AntiforgeryOptions.cs
+++ b/src/Microsoft.AspNetCore.Antiforgery/AntiforgeryOptions.cs
@@ -16,11 +16,17 @@ namespace Microsoft.AspNetCore.Antiforgery
         private string _cookieName;
         private string _formFieldName = AntiforgeryTokenFieldName;
 
+        /// <summary>
+        /// The default cookie prefix, which is ".AspNetCore.Antiforgery.".
+        /// </summary>
+        public static readonly string DefaultCookiePrefix = ".AspNetCore.Antiforgery.";
+
         /// <summary>
         /// Specifies the name of the cookie that is used by the antiforgery system.
         /// </summary>
         /// <remarks>
-        /// If an explicit name is not provided, the system will automatically generate a name.
+        /// If an explicit name is not provided, the system will automatically generate a
+        /// unique name that begins with <see cref="DefaultCookiePrefix"/>.
         /// </remarks>
         public string CookieName
         {
diff --git a/src/Microsoft.AspNetCore.Antiforgery/Internal/AntiforgeryOptionsSetup.cs b/src/Microsoft.AspNetCore.Antiforgery/Internal/AntiforgeryOptionsSetup.cs
index f1f7dc612a..1c5a3fa4b8 100644
--- a/src/Microsoft.AspNetCore.Antiforgery/Internal/AntiforgeryOptionsSetup.cs
+++ b/src/Microsoft.AspNetCore.Antiforgery/Internal/AntiforgeryOptionsSetup.cs
@@ -22,7 +22,7 @@ namespace Microsoft.AspNetCore.Antiforgery.Internal
             if (options.CookieName == null)
             {
                 var applicationId = dataProtectionOptions.ApplicationDiscriminator ?? string.Empty;
-                options.CookieName = ComputeCookieName(applicationId);
+                options.CookieName = AntiforgeryOptions.DefaultCookiePrefix + ComputeCookieName(applicationId);
             }
         }
 
diff --git a/test/Microsoft.AspNetCore.Antiforgery.Test/Internal/AntiforgeryOptionsSetupTest.cs b/test/Microsoft.AspNetCore.Antiforgery.Test/Internal/AntiforgeryOptionsSetupTest.cs
index a981339793..79804b4117 100644
--- a/test/Microsoft.AspNetCore.Antiforgery.Test/Internal/AntiforgeryOptionsSetupTest.cs
+++ b/test/Microsoft.AspNetCore.Antiforgery.Test/Internal/AntiforgeryOptionsSetupTest.cs
@@ -10,8 +10,8 @@ namespace Microsoft.AspNetCore.Antiforgery.Internal
     public class AntiforgeryOptionsSetupTest
     {
         [Theory]
-        [InlineData("HelloWorldApp", "tGmK82_ckDw")]
-        [InlineData("TodoCalendar", "7mK1hBEBwYs")]
+        [InlineData("HelloWorldApp", ".AspNetCore.Antiforgery.tGmK82_ckDw")]
+        [InlineData("TodoCalendar", ".AspNetCore.Antiforgery.7mK1hBEBwYs")]
         public void AntiforgeryOptionsSetup_SetsDefaultCookieName_BasedOnApplicationId(
             string applicationId,
             string expectedCookieName)