Data from a series of 181 patients subjected to long-term follow-up after surgical resection for non-small cell stage I and II lung cancer were analyzed to evaluate the statistical incidence and the prognostic factors of recurrence. The recurrence rate/year was particularly high in the first 2 years after surgery: the 2-year recurrence rate was 35.1% in stage I tumors and 51.8% in stage II, whereas the 5- and 7-year recurrence rates were 46.1 and 55.9% and 65.8 and 70.7%, respectively, for the same groups. Recurrences were observed more frequently in non-epidermoid carcinomas with multiple nodules (100% at 5 years) and in carcinomas classified as stage II (70.7% at 5-7 years), particularly when defined as adenocarcinoma (100% at 3 years). In the overall recurrence rate we observed no significant difference dependent on the type of resection even though limited segmental or wedge resection appeared to be related to a higher risk rate (true recurrence rate ratio: 0.6). Over two-thirds of the first observed recurrences were located at a distant site, with a slightly higher incidence of non-epidermoid carcinoma (72.5%). Isolated local recurrence mostly occurred in epidermoid carcinoma (47.6%). The most frequent sites of recurrence were the brain, bone and mediastinum. On multivariate analysis, independently significant adverse prognostic factors regarding the recurrence incidence were: tumor size greater than 3 cm, bronchial or hilar lymph node involvement, tumor histologically defined as adenocarcinoma, and the presence of satellite nodules.