Pulmonary thromboendarterectomy, the most common surgical treatment of chronic thromboembolic pulmonary hypertension, is being performed with increasing frequency throughout the world. Massive pulmonary hemorrhage is a potentially fatal complication of this procedure. In this report of three such cases, the diagnosis, clinical course, and possible treatments are discussed. Anesthesiologists involved in the care of patients receiving pulmonary thromboendarterectomy must be aware of the possibility of this complication, as well as the various techniques available for its treatment.