diff --git a/backend/app/pypi_proxy.py b/backend/app/pypi_proxy.py
index 54bd59e..0b380c8 100644
--- a/backend/app/pypi_proxy.py
+++ b/backend/app/pypi_proxy.py
@@ -536,13 +536,18 @@ def _cache_dependency_background(
 
             # Parse the HTML to find wheel files
             html = response.text
+
+            # Create pattern that matches both normalized (hyphens) and original (underscores) forms
+            # PEP 503 normalizes to hyphens, but wheel filenames may use underscores
+            name_pattern = re.sub(r'[-_]+', '[-_]+', normalized_name)
+
             # Look for wheel files (.whl) - prefer them over sdist
-            wheel_pattern = rf'href="([^"]*{normalized_name}[^"]*\.whl[^"]*)"'
+            wheel_pattern = rf'href="([^"]*{name_pattern}[^"]*\.whl[^"]*)"'
             matches = re.findall(wheel_pattern, html, re.IGNORECASE)
 
             if not matches:
                 # Try sdist
-                sdist_pattern = rf'href="([^"]*{normalized_name}[^"]*\.tar\.gz[^"]*)"'
+                sdist_pattern = rf'href="([^"]*{name_pattern}[^"]*\.tar\.gz[^"]*)"'
                 matches = re.findall(sdist_pattern, html, re.IGNORECASE)
 
             if not matches: