Lung specimens obtained from wet materials were reviewed for detection of microthrombi. Multiple microthrombi, which were composed mainly of platelets, were seen in the pulmonary arteriole and microcirculation in two autopsy cases with splenectomized thalassemic disease. These findings provide a rational explanation for the increased spontaneous platelet aggregation in the whole blood, and may be an additional factor to the progress of pulmonary dysfunction and hypoxemia seen in splenectomized thalassemic patients.