Signs, symptoms, and laboratory data to support the diagnosis of pulmonary embolism are often deceivingly nonspecific. Ninety patients with documented massive pulmonary embolism had few clinical and laboratory findings traditionally described for pulmonary infarction; only 62% had pleuritic chest pain, 27% had hemoptysis, and 17% had a pleural rub. Fifteen percent had a normal x-ray film of the chest, and only 31% had an electrocardiogram typical of acute cor pulmonale. Fifty-eight percent presented without phlebitis. Dyspnea was the most frequent symptom (80%), and most patients had a well-defined condition, predisposing them to pulmonary embolism.