diff --git a/CHANGES/1630.bugfix.rst b/CHANGES/1630.bugfix.rst
new file mode 100644
index 00000000..e083dc1f
--- /dev/null
+++ b/CHANGES/1630.bugfix.rst
@@ -0,0 +1 @@
+Fix the regex pattern that finds the "bad characters" for deeplink payload.
\ No newline at end of file
diff --git a/aiogram/utils/deep_linking.py b/aiogram/utils/deep_linking.py
index 19cc64c6..fe2764f7 100644
--- a/aiogram/utils/deep_linking.py
+++ b/aiogram/utils/deep_linking.py
@@ -18,7 +18,7 @@ from aiogram.utils.payload import decode_payload, encode_payload
 if TYPE_CHECKING:
     from aiogram import Bot
 
-BAD_PATTERN = re.compile(r"[^A-z0-9-]")
+BAD_PATTERN = re.compile(r"[^a-zA-Z0-9-_]")
 
 
 async def create_start_link(
diff --git a/tests/test_utils/test_deep_linking.py b/tests/test_utils/test_deep_linking.py
index 85a6027b..c5f5259a 100644
--- a/tests/test_utils/test_deep_linking.py
+++ b/tests/test_utils/test_deep_linking.py
@@ -10,12 +10,14 @@ PAYLOADS = [
     "aaBBccDDeeFF5544332211",
     -12345678901234567890,
     12345678901234567890,
+    "underscore_and-dash",
 ]
 WRONG_PAYLOADS = [
     "@BotFather",
     "Some:special$characters#=",
     "spaces spaces spaces",
     1234567890123456789.0,
+    "has`backtick",
 ]