diff --git a/rest_framework_mongoengine/serializers.py b/rest_framework_mongoengine/serializers.py
index 6099848..415e13e 100644
--- a/rest_framework_mongoengine/serializers.py
+++ b/rest_framework_mongoengine/serializers.py
@@ -643,11 +643,6 @@ def build_standard_field(self, field_name, model_field):
             # `allow_blank` is only valid for textual fields.
             field_kwargs.pop('allow_blank', None)
 
-        if field_class is drf_fields.BooleanField and field_kwargs.get('allow_null', False):
-            field_kwargs.pop('allow_null', None)
-            field_kwargs.pop('default', None)
-            field_class = drf_fields.NullBooleanField
-
         return field_class, field_kwargs
 
     def build_compound_field(self, field_name, model_field, child_field):
diff --git a/tests/test_basic.py b/tests/test_basic.py
index 618691d..ea18e1a 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -115,7 +115,7 @@ class Meta:
                 long_field = IntegerField(required=False)
                 float_field = FloatField(required=False)
                 boolean_field = BooleanField(required=False)
-                nullboolean_field = NullBooleanField(required=False)
+                nullboolean_field = BooleanField(allow_null=True, required=False)
                 date_field = DateTimeField(required=False)
                 complexdate_field = DateTimeField(required=False)
                 uuid_field = UUIDField(required=False)
@@ -167,7 +167,7 @@ class Meta:
                 long_field = IntegerField(required=False)
                 float_field = FloatField(required=False)
                 boolean_field = BooleanField(required=False)
-                nullboolean_field = NullBooleanField(required=False)
+                nullboolean_field = BooleanField(allow_null=True, required=False)
                 date_field = DateTimeField(required=False)
                 complexdate_field = DateTimeField(required=False)
                 uuid_field = UUIDField(required=False)