Abstract: The first rare Jk(a-b-) type in China was found in Han, Henan Province, but no moreJk(a-b-) in the proband's family. Her parents and sibs were Jk(a+b-) type and her hu-sband and children were Jk(a-b+) type. The second Jk(a-b-) was found in Hakka, MeiCounty, Guangdong Province, four months later. This proband is a young unmarried woman.No antibody was found in both of these two proband' sera. Up to now Jk(a- b- ) phenotypefrequency in Chinese is 0.03%, and the gene frequency is 0.0202.

Key words: Red cell's blood group; Kidd system; Gene frequency; Chinese