Minisatellite DNA from 13 Rubus cultivars, including five raspberries, two R. flagellaris derivatives, three R. ursinus derivatives, and the three raspberry-blackberry hybrids Boysen, Logan Thornless and Young, was hybridized with the M13 probe yielding cultivar-specific DNA fragment profiles. Estimates of similarity, assessed from the fragment profiles, showed a strong association with the degree of genetic relatedness among the cultivars. Boysen was shown to be closely related to Austin Thornless, Logan and Young, and is thus thought to be of similar origin to Young, that is Austin Thornless x Phenomenal. While genetic relatedness of Creston with Lloyd George was suggested, Lloyd George parentage of Creston cannot be confirmed from the data obtained.