diff --git a/scrapy/downloadermiddlewares/decompression.py b/scrapy/downloadermiddlewares/decompression.py
index 0fcf8fb8c..e01e9cc76 100644
--- a/scrapy/downloadermiddlewares/decompression.py
+++ b/scrapy/downloadermiddlewares/decompression.py
@@ -9,10 +9,19 @@ import tarfile
 import zipfile
 from io import BytesIO
 from tempfile import mktemp
+from warnings import warn
 
+from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.responsetypes import responsetypes
 
 
+warn(
+    'scrapy.downloadermiddlewares.decompression is deprecated',
+    ScrapyDeprecationWarning,
+    stacklevel=2,
+)
+
+
 logger = logging.getLogger(__name__)