The paper presents information on two species of digger wasps, Sceliphron destillatorium (Illiger, 1807) and S. curvatum (Smith, 1870), alien for the fauna of Poland (within its present borders). Both species are presently spreading in the country. Sceliphron destillatorium, a South-Palaearctic species, has been observed in Poland since 1960. Sceliphron curvatum was introduced to Europe from Asia in the 1970s, and at present it is known from many South- and Central-European countries. The species was found for the first time in Poland in 2003. New localities of the two species in Poland are given and issues connected with their present distribution are discussed.