diff --git a/src/Testing/src/AssemblyTestLog.cs b/src/Testing/src/AssemblyTestLog.cs
index 3c598b67d5..611b853fac 100644
--- a/src/Testing/src/AssemblyTestLog.cs
+++ b/src/Testing/src/AssemblyTestLog.cs
@@ -222,7 +222,7 @@ namespace Microsoft.Extensions.Logging.Testing
 
                     // Try to clear previous logs, continue if it fails.
                     var assemblyBaseDirectory = TestFileOutputContext.GetAssemblyBaseDirectory(assembly);
-                    if (!string.IsNullOrEmpty(assemblyBaseDirectory))
+                    if (!string.IsNullOrEmpty(assemblyBaseDirectory) && !TestFileOutputContext.GetPreserveExistingLogsInOutput(assembly))
                     {
                         try
                         {
diff --git a/src/Testing/src/TestFrameworkFileLoggerAttribute.cs b/src/Testing/src/TestFrameworkFileLoggerAttribute.cs
index 025a5a9bd8..1059fa76f2 100644
--- a/src/Testing/src/TestFrameworkFileLoggerAttribute.cs
+++ b/src/Testing/src/TestFrameworkFileLoggerAttribute.cs
@@ -9,8 +9,8 @@ namespace Microsoft.Extensions.Logging.Testing
     [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false)]
     public class TestFrameworkFileLoggerAttribute : TestOutputDirectoryAttribute
     {
-        public TestFrameworkFileLoggerAttribute(string tfm, string baseDirectory = null)
-            : base(tfm, baseDirectory)
+        public TestFrameworkFileLoggerAttribute(string preserveExistingLogsInOutput, string tfm, string baseDirectory = null)
+            : base(preserveExistingLogsInOutput, tfm, baseDirectory)
         {
         }
     }
diff --git a/src/Testing/src/build/Microsoft.Extensions.Logging.Testing.props b/src/Testing/src/build/Microsoft.Extensions.Logging.Testing.props
index 3895cb5471..167efb3f82 100644
--- a/src/Testing/src/build/Microsoft.Extensions.Logging.Testing.props
+++ b/src/Testing/src/build/Microsoft.Extensions.Logging.Testing.props
@@ -9,6 +9,11 @@
   <Target Name="SetLoggingTestingAssemblyAttributes"
     BeforeTargets="GetAssemblyAttributes"
     Condition="'$(GenerateLoggingTestingAssemblyAttributes)' != 'false'">
+    <PropertyGroup>
+      <PreserveExistingLogsInOutput Condition="'$(PreserveExistingLogsInOutput)' == '' AND '$(ContinuousIntegrationBuild)' == 'true'">true</PreserveExistingLogsInOutput>
+      <PreserveExistingLogsInOutput Condition="'$(PreserveExistingLogsInOutput)' == ''">false</PreserveExistingLogsInOutput>
+    </PropertyGroup>
+
     <ItemGroup>
       <AssemblyAttribute Include="Xunit.TestFramework">
         <_Parameter1>Microsoft.AspNetCore.Testing.AspNetTestFramework</_Parameter1>
@@ -16,8 +21,9 @@
       </AssemblyAttribute>
 
       <AssemblyAttribute Include="Microsoft.Extensions.Logging.Testing.TestFrameworkFileLoggerAttribute">
-        <_Parameter1>$(TargetFramework)</_Parameter1>
-        <_Parameter2 Condition="'$(LoggingTestingDisableFileLogging)' != 'true'">$(LoggingTestingFileLoggingDirectory)</_Parameter2>
+        <_Parameter1>$(PreserveExistingLogsInOutput)</_Parameter1>
+        <_Parameter2>$(TargetFramework)</_Parameter2>
+        <_Parameter3 Condition="'$(LoggingTestingDisableFileLogging)' != 'true'">$(LoggingTestingFileLoggingDirectory)</_Parameter3>
       </AssemblyAttribute>
     </ItemGroup>
   </Target>
diff --git a/src/Testing/test/AssemblyTestLogTests.cs b/src/Testing/test/AssemblyTestLogTests.cs
index 6d7ae5139a..dbefa4ccd2 100644
--- a/src/Testing/test/AssemblyTestLogTests.cs
+++ b/src/Testing/test/AssemblyTestLogTests.cs
@@ -8,6 +8,7 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text.RegularExpressions;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.Extensions.Logging.Testing.Tests
@@ -18,6 +19,17 @@ namespace Microsoft.Extensions.Logging.Testing.Tests
         private static readonly string ThisAssemblyName = ThisAssembly.GetName().Name;
         private static readonly string TFM = new DirectoryInfo(AppContext.BaseDirectory).Name;
 
+        [Fact]
+        public void FunctionalLogs_LogsPreservedFromNonFlakyRun()
+        {
+        }
+
+        [Fact]
+        [Flaky("http://example.com", FlakyOn.All)]
+        public void FunctionalLogs_LogsPreservedFromFlakyRun()
+        {
+        }
+
         [Fact]
         public void ForAssembly_ReturnsSameInstanceForSameAssembly()
         {