The authors reported the results of field survey and family follow-up on acatalasemia and hypocatalasemia during the years of 1966 and 1967. Thirty-seven hypocatalasemias were seen in the tests of 11,875 individuals at Chiba Prefecture including the examinees tested in 1965. Thus, the rate of incidence at Chiba amounted to 0.31%. The test on students of Okayama University revealed two hypocatalasemias among 2,526 (0.08%). Oki Is. contained seven hypocatalasemias among their 4,831 school-children. And no hypocatalasemic individuals were found out among 2,682 inhabitants of Okinawa Is., Ryukyu. Formosa, however, showed rather high incidence rate such as 0.28%, 60 hypocatalasemias among 21,789 inhabitants. In 1966 and 1967, three acatalasemias of two families, one of them already reported in 1965, were added to the formerly known cases. Consequently, the total of reported acatalasemias were 93 cases of 44 families by the end of 1967.