diff --git a/CHANGES.rst b/CHANGES.rst
index 453bc40..426a56d 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,6 +2,14 @@
 Changelog
 ~~~~~~~~~
 
+Version 0.30.3 (2023-10-30)
+---------------------------
+
+Bugs fixed:
+
+- Regression: a positional argument with an underscore used in `@arg` decorator
+  would cause Argh fail on the assembling stage. (#208)
+
 Version 0.30.2 (2023-10-24)
 ---------------------------
 
diff --git a/pyproject.toml b/pyproject.toml
index 92a3906..26c7cce 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "flit_core.buildapi"
 
 [project]
 name = "argh"
-version = "0.30.2"
+version = "0.30.3"
 description = "An unobtrusive argparse wrapper with natural syntax"
 readme = "README.rst"
 requires-python = ">=3.8"
diff --git a/src/argh/decorators.py b/src/argh/decorators.py
index aad081b..10ede10 100644
--- a/src/argh/decorators.py
+++ b/src/argh/decorators.py
@@ -141,10 +141,11 @@ def wrapper(func: Callable) -> Callable:
             raise CliArgToFuncArgGuessingError("at least one CLI arg must be defined")
 
         func_arg_name = naive_guess_func_arg_name(args)
+        cli_arg_names = [name.replace("_", "-") for name in args]
         completer = kwargs.pop("completer", None)
         spec = ParserAddArgumentSpec.make_from_kwargs(
             func_arg_name=func_arg_name,
-            cli_arg_names=args,
+            cli_arg_names=cli_arg_names,
             parser_add_argument_kwargs=kwargs,
         )
         if completer:
diff --git a/tests/test_decorators.py b/tests/test_decorators.py
index 7ac1d84..b813069 100644
--- a/tests/test_decorators.py
+++ b/tests/test_decorators.py
@@ -33,7 +33,7 @@ def func():
     assert attrs == [
         ParserAddArgumentSpec(
             func_arg_name="foo",
-            cli_arg_names=("foo",),
+            cli_arg_names=["foo"],
             nargs="+",
             other_add_parser_kwargs={
                 "help": "my help",
@@ -41,7 +41,7 @@ def func():
         ),
         ParserAddArgumentSpec(
             func_arg_name="bar",
-            cli_arg_names=("--bar",),
+            cli_arg_names=["--bar"],
             default_value=1,
         ),
     ]
diff --git a/tests/test_integration.py b/tests/test_integration.py
index b2f392d..e70db4f 100644
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -735,14 +735,21 @@ def remind(
     parser = DebugArghParser()
     parser.set_default_command(remind)
 
-    assert "Basil" in parser.format_help()
-    assert "Moose" in parser.format_help()
-    assert "creatures" in parser.format_help()
-
-    # explicit help message is not obscured by the implicit one...
-    assert "remarkable animal" in parser.format_help()
-    # ...but is still present
-    assert "it can speak" in parser.format_help()
+    help_normalised = re.sub(r"\s+", " ", parser.format_help())
+
+    assert "name 'Basil'" in help_normalised
+    assert "-t TASK, --task TASK 'hang the Moose'" in help_normalised
+    assert (
+        "-r REASON, --reason REASON 'there are creatures living in it'"
+        in help_normalised
+    )
+
+    # explicit help message is not obscured by the implicit one
+    # but is still present
+    assert (
+        "-n NOTE, --note NOTE why is it a remarkable animal? "
+        "(default: 'it can speak English')"
+    ) in help_normalised
 
 
 def test_default_arg_values_in_help__regression():
diff --git a/tests/test_regressions.py b/tests/test_regressions.py
index bb49e70..c19115f 100644
--- a/tests/test_regressions.py
+++ b/tests/test_regressions.py
@@ -171,3 +171,12 @@ def func(*, x: TextIO = sys.stdout) -> None:
 
     parser = DebugArghParser()
     parser.set_default_command(func)
+
+
+def test_regression_issue208():
+    @argh.arg("foo_bar", help="fooooo")
+    def func(foo_bar):
+        return foo_bar
+
+    parser = DebugArghParser()
+    parser.set_default_command(func)