Pulmonary infarction is an entity of medical significance that develops concurrently in beta-thalassemia but not in alpha-thalassemia. The reason for this difference is yet to be elucidated. We have evaluated a 21-year-old male alpha-thalassemia-2 patient who had profound microcytic anemia and pulmonary infarction. Analysis of the alpha-globin gene revealed -alpha3.7/alpha alpha genotype. His mother also had the same heterozygous gene deletion, though she had neither anemia nor pulmonary infarction. Since the patient had no other predisposition to pulmonary infarction, it is suggested that there is a close etiologic relationship between morphologic abnormality of the erythrocytes caused by alpha-thalassemia-2 and development of pulmonary infarction.