diff --git a/dotnet/src/Agents/OpenAI/Extensions/ChatContentMessageExtensions.cs b/dotnet/src/Agents/OpenAI/Extensions/ChatContentMessageExtensions.cs
index c627d9517c81..86ed4085a91b 100644
--- a/dotnet/src/Agents/OpenAI/Extensions/ChatContentMessageExtensions.cs
+++ b/dotnet/src/Agents/OpenAI/Extensions/ChatContentMessageExtensions.cs
@@ -44,8 +44,10 @@ public static IEnumerable<ThreadInitializationMessage> ToThreadInitializationMes
     public static ResponseItem ToResponseItem(this ChatMessageContent message)
     {
         var items = message.Items;
-        IEnumerable<ResponseContentPart> contentParts = items.Select(item => item.ToResponseContentPart());
-        return message.Role.Label.ToUpperInvariant() switch
+        var roleLabel = message.Role.Label.ToUpperInvariant();
+
+        IEnumerable<ResponseContentPart> contentParts = items.Select(item => item.ToResponseContentPart(roleLabel == "ASSISTANT"));
+        return roleLabel switch
         {
             "SYSTEM" => ResponseItem.CreateSystemMessageItem(contentParts),
             "USER" => ResponseItem.CreateUserMessageItem(contentParts),
diff --git a/dotnet/src/Agents/OpenAI/Extensions/KernelContentExtensions.cs b/dotnet/src/Agents/OpenAI/Extensions/KernelContentExtensions.cs
index 59f11f0f68cd..010a7b64976b 100644
--- a/dotnet/src/Agents/OpenAI/Extensions/KernelContentExtensions.cs
+++ b/dotnet/src/Agents/OpenAI/Extensions/KernelContentExtensions.cs
@@ -10,11 +10,11 @@ namespace Microsoft.SemanticKernel.Agents.OpenAI;
 /// </summary>
 internal static class KernelContentExtensions
 {
-    internal static ResponseContentPart ToResponseContentPart(this KernelContent content)
+    internal static ResponseContentPart ToResponseContentPart(this KernelContent content, bool isOutput = false)
     {
         return content switch
         {
-            TextContent textContent => textContent.ToResponseContentPart(),
+            TextContent textContent => textContent.ToResponseContentPart(isOutput),
             ImageContent imageContent => imageContent.ToResponseContentPart(),
             BinaryContent binaryContent => binaryContent.ToResponseContentPart(),
             FileReferenceContent fileReferenceContent => fileReferenceContent.ToResponseContentPart(),
@@ -22,9 +22,11 @@ internal static ResponseContentPart ToResponseContentPart(this KernelContent con
         };
     }
 
-    internal static ResponseContentPart ToResponseContentPart(this TextContent content)
+    internal static ResponseContentPart ToResponseContentPart(this TextContent content, bool isOutput)
     {
-        return ResponseContentPart.CreateInputTextPart(content.Text);
+        return isOutput ?
+            ResponseContentPart.CreateOutputTextPart(content.Text, []) : 
+            ResponseContentPart.CreateInputTextPart(content.Text);
     }
 
     internal static ResponseContentPart ToResponseContentPart(this ImageContent content)
diff --git a/dotnet/src/IntegrationTests/Agents/OpenAIResponseAgentTests.cs b/dotnet/src/IntegrationTests/Agents/OpenAIResponseAgentTests.cs
index fcb77d4a7fad..ca20aff1cea3 100644
--- a/dotnet/src/IntegrationTests/Agents/OpenAIResponseAgentTests.cs
+++ b/dotnet/src/IntegrationTests/Agents/OpenAIResponseAgentTests.cs
@@ -218,6 +218,51 @@ public async Task OpenAIResponseAgentInvokeStreamingWithThreadAsync(bool isOpenA
         Assert.Contains("Computer says no", responseText);
     }
 
+
+    /// <summary>
+    /// Integration test for <see cref="OpenAIResponseAgent"/> with existing chat history.
+    /// </summary>
+    [RetryTheory(typeof(HttpOperationException))]
+    [InlineData(false, false)]
+    [InlineData(false, true)]
+    [InlineData(true, false)]
+    [InlineData(true, true)]
+    public async Task OpenAIResponseAgentInvokeStreamingWithChatHistoryAsync(bool isOpenAI, bool storeEnabled)
+    {
+        // Arrange
+        OpenAIResponseClient client = this.CreateClient(isOpenAI);
+        OpenAIResponseAgent agent = new(client)
+        {
+            StoreEnabled = storeEnabled,
+            Instructions = "Answer all queries in English and French."
+        };
+
+        var chatHistory = new ChatHistory();
+        chatHistory.AddUserMessage("Hello my name is John");
+        chatHistory.AddAssistantMessage("Hello John, how can I help you today?");
+        chatHistory.AddUserMessage("What is my Name?");
+
+        AgentThread agentThread = storeEnabled ? new OpenAIResponseAgentThread(client) : new ChatHistoryAgentThread();
+
+        // Act
+        string? responseText = null;
+        try
+        {
+            var responseMessages = await agent.InvokeStreamingAsync(chatHistory, agentThread).ToArrayAsync();
+            responseText = string.Join(string.Empty, responseMessages.Select(ri => ri.Message.Content));
+        }
+        finally
+        {
+            if (agentThread.Id is not null)
+            {
+                await agentThread.DeleteAsync();
+            }
+        }
+
+        // Assert
+        Assert.NotNull(responseText);
+    }
+
     /// <summary>
     /// Integration test for <see cref="OpenAIResponseAgent"/> adding override instructions to a thread on invocation via custom options.
     /// </summary>