diff --git a/src/mutmut/file_mutation.py b/src/mutmut/file_mutation.py
index 2fa50ba6..77f39403 100644
--- a/src/mutmut/file_mutation.py
+++ b/src/mutmut/file_mutation.py
@@ -248,7 +248,7 @@ def function_trampoline_arrangement(function: cst.FunctionDef, mutants: Iterable
         nodes.append(mutated_method) # type: ignore
 
     # trampoline that forwards the calls
-    trampoline = list(cst.parse_module(build_trampoline(orig_name=name, mutants=mutant_names, class_name=class_name)).body)
+    trampoline = list(cst.parse_module(build_trampoline(orig_name=name, mutants=mutant_names, class_name=class_name, asynchronous=function.asynchronous)).body)
     trampoline[0] = trampoline[0].with_changes(leading_lines=[cst.EmptyLine()])
     nodes.extend(trampoline)
 
diff --git a/src/mutmut/trampoline_templates.py b/src/mutmut/trampoline_templates.py
index ad4cc90a..3c6fa1bb 100644
--- a/src/mutmut/trampoline_templates.py
+++ b/src/mutmut/trampoline_templates.py
@@ -1,6 +1,6 @@
 CLASS_NAME_SEPARATOR = 'ǁ'
 
-def build_trampoline(*, orig_name, mutants, class_name):
+def build_trampoline(*, orig_name, mutants, class_name, asynchronous):
     mangled_name = mangle_function_name(name=orig_name, class_name=class_name)
 
     mutants_dict = f'{mangled_name}__mutmut_mutants : ClassVar[MutantDict] = {{\n' + ', \n    '.join(f'{repr(m)}: {m}' for m in mutants) + '\n}'
@@ -17,8 +17,8 @@ def build_trampoline(*, orig_name, mutants, class_name):
     return f"""
 {mutants_dict}
 
-def {orig_name}({'self, ' if class_name is not None else ''}*args, **kwargs):
-    result = {trampoline_name}({access_prefix}{mangled_name}__mutmut_orig{access_suffix}, {access_prefix}{mangled_name}__mutmut_mutants{access_suffix}, args, kwargs{self_arg})
+{'async ' if asynchronous is not None else ''}def {orig_name}({'self, ' if class_name is not None else ''}*args, **kwargs):
+    result = {'await ' if asynchronous is not None else ''} {trampoline_name}({access_prefix}{mangled_name}__mutmut_orig{access_suffix}, {access_prefix}{mangled_name}__mutmut_mutants{access_suffix}, args, kwargs{self_arg})
     return result 
 
 {orig_name}.__signature__ = _mutmut_signature({mangled_name}__mutmut_orig)