ABO saliva blood groups, 21 enzyme, 7 serum protein and the haemoglobin systems of 56 baboons and 61 vervets from South Africa were tested. Baboons were found to have a high frequency (0.728) of blood group A, 6 PGD and transferrin systems were polymorphic, and haptoglobins were subtyped. Variation also occurred in CA, MDH, PGK, PGM2, Pep B, α1-antitrypsin and caeruloplasmin systems. Vervets were polymorphic in ADA, α1-antitrypsin and caeruloplasmin systems and haptoglobins were subtyped. Variation also occurred in Pep D system. Phenotype frequencies varied according to area of origin in both species.