Three new glucose-6-phosphate dehydrogenase (G6PD) variants, which showed electrophoretically normal mobility and were associated with chronic nonspherocytic hemolytic anemia, were found in Japan. G6PD Ogikubo, found in a 17-year-old male whose red cells contained 3% of normal enzyme activity, had normal Km G6P, normal Km NADP, normal utilization of deamino-NADP, decreased heat stability, and a normal pH curve. G6PD Yokohama, characterized from a 15-year-old male, had 1.9% of normal enzyme activity, normal Km G6P, normal Km NADP, low Ki NADPH, normal utilizations of both 2-deoxy-G6P and deamino-NADP, decreased heat stability, and normal pH curve. G6PD Akita, characterized from a 56-year-old male, had an undetectably low activity when hemolysate was examined, normal Km G6P, normal Km NADP, normal Ki NADPH, normal utilizations of both 2-deoxy-G6P and deamino-NADP, decreased heat stability, and normal pH curve. The degree of hemolytic anemia was moderate to mild in all three patients.