The Kidd locus phenotype Jk(a-b-) was detected in 0.9 percent of Polynesians living in New Zealand. Over a period of 13 years, nine examples of anti-Jk3 were detected, one of which caused a delayed hemolytic transfusion reaction. Other examples resulted in mild hemolytic disease of the newborn. The anti-Jk3 reacted as an inseparable antibody, confirmed that inheritance of the Jk(a-b-) phenotype was best explained by the presence of a silent Jk allele.