diff --git a/private_gpt/components/llm/prompt_helper.py b/private_gpt/components/llm/prompt_helper.py
index 985d217..7715820 100644
--- a/private_gpt/components/llm/prompt_helper.py
+++ b/private_gpt/components/llm/prompt_helper.py
@@ -173,18 +173,22 @@ class TagPromptStyle(AbstractPromptStyle):
 
 class MistralPromptStyle(AbstractPromptStyle):
     def _messages_to_prompt(self, messages: Sequence[ChatMessage]) -> str:
-        prompt = "<s>"
+        inst_buffer = []
+        text = ""
         for message in messages:
-            role = message.role
-            content = message.content or ""
-            if role.lower() == "system":
-                message_from_user = f"[INST] {content.strip()} [/INST]"
-                prompt += message_from_user
-            elif role.lower() == "user":
-                prompt += "</s>"
-                message_from_user = f"[INST] {content.strip()} [/INST]"
-                prompt += message_from_user
-        return prompt
+            if message.role == MessageRole.SYSTEM or message.role == MessageRole.USER:
+                inst_buffer.append(str(message.content).strip())
+            elif message.role == MessageRole.ASSISTANT:
+                text += "<s>[INST] " + "\n".join(inst_buffer) + " [/INST]"
+                text += " " + str(message.content).strip() + "</s>"
+                inst_buffer.clear()
+            else:
+                raise ValueError(f"Unknown message role {message.role}")
+
+        if len(inst_buffer) > 0:
+            text += "<s>[INST] " + "\n".join(inst_buffer) + " [/INST]"
+
+        return text
 
     def _completion_to_prompt(self, completion: str) -> str:
         return self._messages_to_prompt(
diff --git a/tests/test_prompt_helper.py b/tests/test_prompt_helper.py
index 3b5af91..ef76437 100644
--- a/tests/test_prompt_helper.py
+++ b/tests/test_prompt_helper.py
@@ -69,17 +69,21 @@ def test_tag_prompt_style_format_with_system_prompt():
 def test_mistral_prompt_style_format():
     prompt_style = MistralPromptStyle()
     messages = [
-        ChatMessage(content="You are an AI assistant.", role=MessageRole.SYSTEM),
-        ChatMessage(content="Hello, how are you doing?", role=MessageRole.USER),
+        ChatMessage(content="A", role=MessageRole.SYSTEM),
+        ChatMessage(content="B", role=MessageRole.USER),
     ]
-
-    expected_prompt = (
-        "<s>[INST] You are an AI assistant. [/INST]</s>"
-        "[INST] Hello, how are you doing? [/INST]"
-    )
-
+    expected_prompt = "<s>[INST] A\nB [/INST]"
     assert prompt_style.messages_to_prompt(messages) == expected_prompt
 
+    messages2 = [
+        ChatMessage(content="A", role=MessageRole.SYSTEM),
+        ChatMessage(content="B", role=MessageRole.USER),
+        ChatMessage(content="C", role=MessageRole.ASSISTANT),
+        ChatMessage(content="D", role=MessageRole.USER),
+    ]
+    expected_prompt2 = "<s>[INST] A\nB [/INST] C</s><s>[INST] D [/INST]"
+    assert prompt_style.messages_to_prompt(messages2) == expected_prompt2
+
 
 def test_chatml_prompt_style_format():
     prompt_style = ChatMLPromptStyle()