After ingesting fava beans, a 26-month-old Chinese-Japanese male infant showed a sickly complexion and yellowish-brownish skin and was hospitalized. Severe hemolytic anemia was observed on admission, and transfusion of 200 ml of packed red cells was required. Red cell enzyme assay revealed that the patient and the mother were deficient in glucose-6-phosphate dehydrogenase (G6PD). Subsequent molecular analysis showed that the patient had a missense mutation 1376 G to T (G6PD Canton) and his mother was a homozygote for the mutation. The patient was a son of a Chinese (Taiwanese) mother and a Japanese father. Although G6PD deficiency is rare in the original Japanese population, the number of "imported" cases could be rising rapidly. This is the first reported Japanese case of G6PD deficiency with G6PD Canton.