diff --git a/PFERD/crawl/ilias/kit_ilias_html.py b/PFERD/crawl/ilias/kit_ilias_html.py
index 636fa68..61df57a 100644
--- a/PFERD/crawl/ilias/kit_ilias_html.py
+++ b/PFERD/crawl/ilias/kit_ilias_html.py
@@ -461,3 +461,55 @@ def _tomorrow() -> date:
 
 def _sanitize_path_name(name: str) -> str:
     return name.replace("/", "-").replace("\\", "-").strip()
+
+
+def deduplicate_element_names(elements: List[IliasPageElement]) -> List[IliasPageElement]:
+    """
+    De-duplicates element names by appending an incrementing number to later elements:
+      test.pdf
+      test.pdf
+    would result in
+      test.pdf
+      test_1.pdf
+
+    It is also space-aware:
+      "te st.pdf"
+      "te st.pdf"
+    would result in
+      "tes st.pdf"
+      "tes st 1.pdf"
+    """
+    known_names = dict()
+    result_elements = []
+
+    for element in elements:
+        # This file is new - add it and mark its name as used
+        if element.name not in known_names:
+            known_names[element.name] = 1
+            result_elements.append(element)
+            continue
+
+        # This file is a duplicate. Find a suitable suffix
+        current_counter = known_names[element.name]
+        adjusted_element = _append_number(element, current_counter)
+        # increment the counter so the next duplicate does not conflict
+        known_names[element.name] += 1
+        # also block the new name, so another file with the *renamed* name gets renamed as well
+        known_names[adjusted_element.name] = 1
+
+        result_elements.append(adjusted_element)
+
+    return result_elements
+
+
+def _append_number(element: IliasPageElement, number: int) -> IliasPageElement:
+    extension_index = element.name.rfind(".")
+    suffix = f" {number}" if " " in element.name else f"_{number}"
+    if extension_index < 0:
+        new_name = element.name + suffix
+    else:
+        new_name = element.name[:extension_index] + suffix + element.name[extension_index:]
+
+    return IliasPageElement(
+        element.type, element.url, new_name, element.mtime, element.description
+    )
diff --git a/PFERD/crawl/ilias/kit_ilias_web_crawler.py b/PFERD/crawl/ilias/kit_ilias_web_crawler.py
index 445997f..222e1d6 100644
--- a/PFERD/crawl/ilias/kit_ilias_web_crawler.py
+++ b/PFERD/crawl/ilias/kit_ilias_web_crawler.py
@@ -15,7 +15,7 @@ from ...utils import fmt_path, soupify, url_set_query_param
 from ..crawler import CrawlError, CrawlWarning, anoncritical
 from ..http_crawler import HttpCrawler, HttpCrawlerSection
 from .file_templates import link_template_plain, link_template_rich
-from .kit_ilias_html import IliasElementType, IliasPage, IliasPageElement
+from .kit_ilias_html import IliasElementType, IliasPage, IliasPageElement, deduplicate_element_names
 
 TargetType = Union[str, int]
 
@@ -214,6 +214,7 @@ class KitIliasWebCrawler(HttpCrawler):
 
         # Fill up our task list with the found elements
         await gather_elements()
+        elements = deduplicate_element_names(elements)
         tasks = [self._handle_ilias_element(PurePath("."), element) for element in elements]
 
         # And execute them
@@ -240,6 +241,7 @@ class KitIliasWebCrawler(HttpCrawler):
 
         # Fill up our task list with the found elements
         await gather_elements()
+        elements = deduplicate_element_names(elements)
         tasks = [self._handle_ilias_element(path, element) for element in elements]
 
         # And execute them