This study assesses the feasibility and toxicity of adoptive immunotherapy with tumor infiltrating lymphocytes and recombinant interleukin-2 in 29 patients who underwent resection for stage III non-small-cell lung cancer. In five patients cultures yielded no growth of tumor infiltrating lymphocytes. In the remaining 24 patients (stage IIIa, 14 cases; stage IIIb, 10 cases) tumor infiltrating lymphocytes were in vitro expanded from surgically obtained tissue samples, including samples from both the tumor and surrounding lung. A number of tumor infiltrating lymphocytes, ranging from 4 to 70 billion cells, were reinfused intravenously 4 to 6 weeks after operation. Interleukin-2 was administered subcutaneously at escalating does for 2 weeks and then at reduced doses for 2 to 3 months. Median survival was 14 months, and the 2-year survival was 40%. Three patients remain alive and disease-free at more than 2 years after operation. Two of these patients did not have complete resection at thoracotomy. Multivariate analysis showed no correlation between the factor of incomplete resection and survival. Intrathoracic recurrence without concomitant distant failure was documented in two patients only and none of the patients with incomplete resection (12 cases) had relapse within the thorax. The present experience demonstrates that adoptive immunotherapy may be applied with safety in patients operated on for stage III non-small-cell lung cancer and suggests that it can be useful, notably in patients with locally advanced disease.