diff --git a/pyrit/memory/storage/serializers.py b/pyrit/memory/storage/serializers.py
index 44b2a04f7f..baec2d6c58 100644
--- a/pyrit/memory/storage/serializers.py
+++ b/pyrit/memory/storage/serializers.py
@@ -491,7 +491,7 @@ def __init__(self, *, category: str, prompt_text: str, extension: str | None = N
         self.value = prompt_text
         self.data_sub_directory = f"/{category}/urls"
         self.file_extension = extension if extension else "txt"
-        self.on_disk = not (prompt_text.startswith(("http://", "https://")))
+        self.on_disk = not (prompt_text.lower().startswith(("http://", "https://")))
 
     def data_on_disk(self) -> bool:
         """