Pulmonary artery tumors are rare and a frequently overlooked cause of pulmonary artery occlusion. The presentation is one of progressive pulmonary dysfunction and right ventricular failure. The diagnosis seldom is made preoperatively. We report 6 cases of primary sarcoma of the pulmonary artery identified at operation, which were treated surgically. Resection with or without adjuvant therapy currently offers the only chance for survival. Emphasis must be placed on earlier identification of these tumors.