Over a period of eleven years (1983-1993), the role of adjuvant chemo and/or radiotherapy was evaluated on 222 resected patients (pts) with NSCLC at atage IIIA(N2). All the patients underwent an attentive mediastinal limphoadenectomy. Fifty-five patients had a clinical mediastinal node involvement. 174 pts had a single mediastinal node station involved while 48 had two or more stations involved. One hundred and seventy-one pts (77%) underwent adjuvant therapies, consisting of citotoxic chemotherapy in 40 pts, radioterhapy in 97 pts and chemoradioterhapy in 34 pts. Follow-up lasted until September 1994. Overall 5-yr survival was 17.5%, the median being 17 months. Forty-two pts were, at that moment, still living (median 43.5 months, min 11-max 120) with 37 disease free. We verified a significant difference concerning survival among the three histologic types (p = 0.03), with the squamous achieving the best result (21.3% at 5-yrs). Surgical N2 had a better survival (20/5% at 5-yrs) than the clinical one (9%), (p = 0.01). In particular, if only one nodal station was involved, survival was 21.3% compared to 4.5% when metastases were present at two or more nodal station (p = 0.0001). Considering the level of mediastinal node involvement, the worst prognosis was linked to the carina node metastases (p = 0.02). Survival benefits were obtained by means of adjuvant therapies (20/2% vs 8.1%), (p = 0.0002). Analyzing all the pts, the best survival was achieved in those treated by surgery plus chemo-radiotherapy (32.4%), (p = 0.0001). As regards the squamous cell tumors, pts who underwent surgery plus radiotherapy had the best prognosis (24.2%), (p = 0.0026). Further, in non-squamous cell tumor, chemo-radiotherapy increased survival (45%), (p = 0.0001). At multivariate analysis, only the level of nodal involvement and the adjuvant therapy maintained their statistical significance. Our results prompt us to conclude that: 1) Squamous cell tumors and single nodal station involvement are linked to the best prognosis; 2) Squamous cell carcinoma should be treated by adjuvant radiotherapy; 3) Non-squamous tumors should undergo to chemo-radiotherapy; 4) Clinical N2 (according to our recent experience) may benefit from neoadjuvant chemotherapy.