We sought to evaluate the effect of new diagnostic modalities on patients explored surgically for inoperable lung cancer. From July 1983 to February 1992, 335 patients underwent thoracotomy for lung cancer. Thirty-three of the 35 patients with nonresectable disease had sufficient data for analysis and underwent chest radiography (CXR), CT scan, and bronchoscopy. The study was terminated when video-assisted thoracoscopy (VAT) was introduced at the institution. Causes of nonresectability included significant N2 disease not diagnosed preoperatively (n = 11), tumor invasion of contiguous mediastinal structures (n = 8), and insufficient pulmonary function (n = 4). Four patients were left with unresected disease because of thoracic metastasis. Two patients had technically unresectable disease; three patients were explored surgically because diagnoses could be obtained by no other means. One patient was found to have small cell cancer. Data analysis demonstrated that 19 of 33 thoracotomies could potentially have been avoided or resulted in resection with current techniques. Refinement of imaging criteria, a judicious surgical approach to N2 disease, and VAT may significantly reduce thoracotomies for nonresectable lung cancer.