At present 40 kinds of abnormal hemoglobins in 55 families, 4 families with a-thalassemia including HbH disease, 35 β-thalassemia including 4 homozygous β-thalassemia, 6 σβ-thalassemia including one homozygous σβ-thalassemia and one HbE-β-thalassemia have been reported in Japan. About 30% of the patients with abnormal hemoglobin and 45% of thalassemia patients were associated with hemolytic anemia. About 95% of the propositi of thalassemia had various degrees of anemia. Increasing number of patients and carriers of abnormal hemoglobin and thalassemia are expected to be discovered in Japan in the future studies.