During International Biological Programme studies in Papua New Guinea, on Karkar Island and at Lufa in the Eastern Highlands, information on anthropometric, biochemical and genetic characteristics was collected from the same individuals. Use has been made of this special situation to investigate whether any associations exist between genetic markers and anthropometric and biochemical variation. Those found, and which satisfy criteria established to help in distinguishing real from chance associations, include: P with haemoglobin concentration and serum albumin and cholesterol levels; acid phosphatase with serum albumin level and haemoglobin concentration; anhaptoglobinaemia and serum globulin level; haemoglobin J-Tongariki with serum phosphorus level. The associations are discussed in terms of their arising from the direct result of environmental factors modifying gene expression, chance concordance of environmental and genetic variation, or pleiotropy.