445 strains of Staphylococcus aureus were isolated from poultry and further 345 strains were isolated from the personnel of a poultry processing plant. The strains were typed with the International Basic Set and a set of poultry phages according to Gibbs et al. (1978b). In total, it was possible to type 38% more of the staphlococci with the poultry set than with the human set, of which the most frequent phage reaction occurred in phage groups III (human set) and B1 (poultry set). 83% of all the strains which were not typable, using the International Basic Set, were however typable with the poultry set. - Poultry specific staphylococci, classified according to biochemical characteristics, in general did not react with the human set. They did, however, show the most frequent reaction in phage groups A and A/B2 of the poultry set. - The human specific strains were almost all typable with the International Basic Set. They also reacted frequently with the phage group B1 of the poultry set, mainly in combinations of B1/III and B1/NT. - In contrast to the International Basic Set, the poultry phage set exhibited a lower specifiy, in that a greater number of strains were typable with the poultry set which were classified by biochemical characteristics as human specific. - It was also possible to type about 70% of the human staphylococci with both sets. A clear classification into the poultry biotype appeared to be possible only with strains reacting with phages of group A of the poultry set.