During a review of a la. rge series of a. utopsies of tha. la. ssaemia patients in our hospital a very significant proportion was found to have pulmona. ry arterial obstructive lesions. A seaxch of previous reports (Cooley et al., 1927; Cooley and Lee, 1933; Whipple and Bradford, 1936; Ellis et al., 1954; Witzleben and Wyatt, 1961; Bhamarapravati et al., 1967; Fessas and Loukopoulos, 1974) on pathology of thalassaemia failed to find an identica. l feature. This is of great interest in its pathogenesis, clinico-physiological implications and management. Patients with severe thalassa, emia. often exhibit dyspnoea., orthopnoea, sometimes chest pains, symptoms usua. lly attributable to anaemia and cardia. c embamssment, and death from cardia. c failure is frequent. With this new finding it rema. ins to be eva. luated how much of the above symptoms and cardiac fa. ilure a. re contributed by the frequent pulmonary a. rteria. l obstructions in addition to anaemia and iron deposition in the heart.