The role of neoadjuvant chemotherapy in stage IIIa non-small cell lung cancer remains undefined. Since 1987, 27 patients with non-small cell lung cancer, all with histologically confirmed metastases to the ipsilateral mediastinal lymph nodes, have been enrolled in an ongoing prospective, randomized trial at our institution. Thirteen patients have been randomized to preoperative etoposide-platinum (EP) chemotherapy-surgery-postoperative EP, and 14 other patients have been randomized to surgery-postoperative mediastinal irradiation (SRT). Both groups are similar in sex, age, weight loss, tumor location, preoperative pulmonary function, physiologic grade, and tumor histology. Eight of the 13 EP patients have responded as evidenced by a 50% or greater radiographic tumor shrinkage after two cycles. Complete tumor and nodal resection rates were similar: 11/13 EP patients versus 12/14 SRT patients. There was no operative mortality for the 27 patients. Median potential follow-up is 29.9 months for the EP group and 34.9 months for the SRT group. Preliminary results suggest a trend toward increased survival time for the EP group (median, 28.7 months) versus the SRT group (median, 15.6 months) (p2 = 0.095). Eleven of 12 resected SRT patients have had recurrence versus 8 of 11 resected EP patients. Time to recurrence reveals no significant differences between the two groups but a trend toward increased disease-free interval in the EP group (12.7 months versus 5.8 months, EP versus SRT). This interim analysis demonstrates the feasibility of such a trial; however, despite the trends, definitive conclusions await further accrual and study maturation.