A series of blood samples for Fuyuge speakers in Papua New Guinea have been tested for genetic variation in haemoglobin and in 8 blood groups, 5 serum protein and 15 enzyme systems, the latter being controlled by genes at 20 loci. Polymorphic variation was present for the ABO, MNS, Rh, P, and Lewis blood group systems, for the Hp and Tf serum protein systems and for the acid phosphatase, 6-PGD, ADA, PGM1· and PGM2 loci controlling red cell enzymes. In addition, a small number of variants was detected in the Pep D system, and a single G6PD deficient male was found. No Hb variants were present, and there was no variation for the Fy, Ge and K blood groups, for the caeruloplasmin, protease inhibitor and albumin serum proteins or for the AK, ‘oxidase’, Pep A, B and C, PHI, diaphorase, ICD, GOT, LDH, MDH and PGK red cell enzyme systems. The results are discussed in relation to similar studies for other populations in Papua New Guinea.