The performance of 92 Holstein-Friesian bulls, which were accepted for progeny testing under the South African National Dairy Animal Performance and Progeny Testing Scheme during 1982, 1983 and 1984, was compared. Bulls which were locally bred for more than one generation were not entered under the Scheme. Only 36% of bulls with local sires were accepted and the majority of Dutch Friesian type bulls were rejected as potential AI bulls. The RBVs (relative breeding values) for milk, butterfat and protein yields of the test bulls were used in the analysis. The factors that were included were GROUP (in which the bull was tested), IMP (the proportion of imported genes), %HOLSTEIN and BREEDER. The factor %HOLSTEIN was found to be significantly related to RBV.milk, RBV.butterfat and RBV.protein (P  < 0.05). IMP (P  < 0.05) was also found to be significantly related to RBV.butterfat. The Holstein type bulls were more successful than the Dutch Friesian type bulls, as an increasing number of Holstein genes leads to higher breeding values for milk, protein and butterfat yields. Bulls with a high percentage Holstein genes are thus more readily accepted as AI bulls. The Holstein will probably gain in popularity and replace the Dutch Friesian type in South Africa.