In patients with disseminated nonseminomatous testicular germ cell tumors (NSTGCT), a retroperitoneal residual tumor mass (RRTM) and/or a pulmonary residual tumor mass (PRTM) are often present after successful treatment with cisplatin-based polychemotherapy. Results and complications of postchemotherapy resection of PRTM were studied and survival was calculated. In the period 1979 to 1996, 31 patients with a median age of 28 years (range, 17 to 44 years) underwent 32 thoracotomies for the resection of a PRTM. A solitary lesion was encountered nine times (28.1%) and multiple lesions were encountered 23 times (71.9%). The median size was 15 mm (range, 2 to 60 mm). There were only three major postoperative complications (9.6%): prolonged ventilation, pneumothorax, and pneumonia. In 16 patients (51.6%), the resected PRTM showed mature teratoma, while in four patients (12.9%) it showed viable cancer. In 11 patients only necrosis and/or fibrosis were found (35.5%). Resection of an RRTM had been performed prior to thoracotomy in 20 patients. There was dissimilarity between the histologic features of the resected RRTM and PRTM in 10 of the 20 patients (50%). During a median follow-up of 80 months (range, 2.5 to 203 months), five patients died from metastatic disease (16.1%). The 5-year survival rate was 86.8% and the 10-year survival rate was 82.2%. Owing to the dissimilarity between the histologic features of the postchemotherapy resected RRTM and PRTM in 50% of the patients, all sites of pulmonary residual disease must be resected in patients with disseminated NSTGCT, irrespective of the histologic features of previously resected retroperitoneal residual disease. This approach offers minimal morbidity and a high 10-year survival rate.