A phase II study was conducted to examine the efficacy of interleukin-2 (IL-2) with lymphokine-activated killer (LAK) cells as therapy for advanced non-small-cell lung carcinoma (NSCLC). IL-2 was administered at a fixed dose of 6 x 10(6) U/M2 per day as a 24 h continuous intravenous infusion (CIV) with LAK cells. Eleven patients were entered onto this study and six were evaluable. One patient had a near complete response of 18 months duration. Only two patients were able to complete the regimen without dose reduction. This regimen was poorly tolerated with pulmonary toxicity being the major problem. The partial responder was the only patient to undergo more than one course of therapy. IL-2/LAK therapy may have activity in NSCLC and further studies are warranted in this uniformly fatal disease. However, future studies will have to incorporate less toxic IL-2 regimens.