Kesselimyia chandleri n.gen., n.sp. is described from material collected in southern Moravia (Havraníky near Znojmo, Czechoslovakia). The larvae and puparia were found in a rotting mushroom of Lepiota sp., 2♂ and 17 ♀ emerged under laboratory conditions. The description of the new species was based mainly on the structure of the male genitalia. Figures of the most important diagnostic characters of the male, female and larvae are provided.