diff --git a/CHANGELOG.md b/CHANGELOG.md
index b47e55ff0..30713bb06 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,8 @@
   ([#6543](https://github.com/mitmproxy/mitmproxy/pull/6543), @mhils)
 * DNS resolution is now exempted from `--ignore-hosts` in WireGuard Mode.
   ([#6513](https://github.com/mitmproxy/mitmproxy/pull/6513), @dsphper)
+* Fix case sensitivity of URL added to blocklist
+  ([#6493](https://github.com/mitmproxy/mitmproxy/pull/6493), @emanuele-em)
 * Fix a bug where logging was stopped prematurely during shutdown.
   ([#6541](https://github.com/mitmproxy/mitmproxy/pull/6541), @mhils)
 * For plaintext traffic, `--ignore-hosts` now also takes HTTP/1 host headers into account.
diff --git a/mitmproxy/flowfilter.py b/mitmproxy/flowfilter.py
index 52db22be0..840583f3d 100644
--- a/mitmproxy/flowfilter.py
+++ b/mitmproxy/flowfilter.py
@@ -402,6 +402,7 @@ class FUrl(_Rex):
     code = "u"
     help = "URL"
     is_binary = False
+    flags = re.IGNORECASE
 
     # FUrl is special, because it can be "naked".
 
diff --git a/test/mitmproxy/addons/test_blocklist.py b/test/mitmproxy/addons/test_blocklist.py
index 9187443b2..b7c7e536d 100644
--- a/test/mitmproxy/addons/test_blocklist.py
+++ b/test/mitmproxy/addons/test_blocklist.py
@@ -22,20 +22,21 @@ def test_parse_spec_err(filter, err):
 
 class TestBlockList:
     @pytest.mark.parametrize(
-        "filter,status_code",
+        "filter,request_url,status_code",
         [
-            (":~u example.org:404", 404),
-            (":~u example.com:404", None),
-            ("/!jpg/418", None),
-            ("/!png/418", 418),
+            (":~u example.org:404", b"https://example.org/images/test.jpg", 404),
+            (":~u example.com:404", b"https://example.org/images/test.jpg", None),
+            (":~u test:404", b"https://example.org/images/TEST.jpg", 404),
+            ("/!jpg/418", b"https://example.org/images/test.jpg", None),
+            ("/!png/418", b"https://example.org/images/test.jpg", 418),
         ],
     )
-    def test_block(self, filter, status_code):
+    def test_block(self, filter, request_url, status_code):
         bl = blocklist.BlockList()
         with taddons.context(bl) as tctx:
             tctx.configure(bl, block_list=[filter])
             f = tflow.tflow()
-            f.request.url = b"https://example.org/images/test.jpg"
+            f.request.url = request_url
             bl.request(f)
             if status_code is not None:
                 assert f.response.status_code == status_code