Between January 1979 and December 1980, 52 patients with completely resected stages II and III non-small-cell lung cancer (NSCLC) were randomly assigned to receive either adjuvant chemotherapy (cyclophosphamide, doxorubicin, and vincristine--CAV) plus intrapleural bacillus Calmette-Guerin (BCG) (n = 26) or adjuvant CAV alone (n = 26). Careful intraoperative staging was performed in all patients, and stratification for histology (squamous versus nonsquamous) and stage (II or III) ensured a balanced randomization for these factors. With a median follow-up time of 111 months, overall 10-year and median survival were 21% and 20 months (range 2-127 + months), respectively. Thirty-four (95%) patients relapsed in extrathoracic sites, and five (5%) developed loco-regional recurrence; their overall median disease-free interval (DFI) was 10 months (range 1-73 months). There was a 9% and 2.5 month difference in survival (p = .76) and disease-free interval (p = .67), respectively, favoring the BCG arm. There were no significant differences in the sites and patterns of first recurrence comparing the two treatment arms. In conclusion, there is no suggestion of a significant therapeutic advantage from intrapleural BCG in conjunction with adjuvant chemotherapy for completely resected stages II and III NSCLC.