diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4fcde83..da36371 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
-
+### Added
+- Display a warning if two or more courses/folders have the same name ([#31])
+ 
 ## [0.3.3] - 2022-03-21
 ### Addded
 - `--all` flag to download all courses ([#30])
@@ -153,6 +155,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [0.1.0] - 2020-04-21
 (undocumented)
 
+[#31]: https://github.com/FliegendeWurst/KIT-ILIAS-downloader/issues/31
 [#30]: https://github.com/FliegendeWurst/KIT-ILIAS-downloader/issues/30
 [#28]: https://github.com/FliegendeWurst/KIT-ILIAS-downloader/pull/28
 [#27]: https://github.com/FliegendeWurst/KIT-ILIAS-downloader/issues/27
diff --git a/src/ilias/folder.rs b/src/ilias/folder.rs
index 962192a..92cbfb2 100644
--- a/src/ilias/folder.rs
+++ b/src/ilias/folder.rs
@@ -1,4 +1,4 @@
-use std::{path::Path, sync::Arc};
+use std::{path::Path, sync::Arc, collections::HashSet};
 
 use anyhow::{Context, Result};
 
@@ -20,11 +20,17 @@ pub async fn download(path: &Path, ilias: Arc<ILIAS>, url: &URL) -> Result<()> {
 				.context("failed to write folder page html")?;
 		}
 	}
+	let mut names = HashSet::new();
 	for item in content.0 {
 		let item = item?;
-		let path = path.join(file_escape(
+		let item_name = file_escape(
 			ilias.course_names.get(item.name()).map(|x| &**x).unwrap_or(item.name()),
-		));
+		);
+		if names.contains(&item_name) {
+			warning!(format => "folder {} contains duplicated folder {:?}", path.display(), item_name);
+		}
+		names.insert(item_name.clone());
+		let path = path.join(item_name);
 		let ilias = Arc::clone(&ilias);
 		spawn(process_gracefully(ilias, path, item));
 	}