Despite the increasing frequency of lung cancer, the percentage occurring in young patients is very low (1.3-5.5% of all lung cancers). In 1992, of the 78,124 cases observed in Italy, 2.8% involved patients under 40 years of age. We reviewed a series of 800 patients with histologically proven lung cancer, candidates to a long-term follow-up. Of these, 23 (2.9%) were under 40 years of age, with a low male/female ratio (1.87:1). Fifty-two percent were smokers and 82.6% presented symptoms as the time of diagnosis. The most frequent histologic types were adenocarcinoma and large-cell type, which carried a better outcome (10-year survival of 28.5%) than epidermoid and small-cell types (p = 0.013). These tumors detected in 13% and 17.4% of cases, were unresectable (except for one epidermoid carcinoma), with a survival expectancy of 0% at two years. Considering all patients, resection was possible in nine cases, being curative in seven, with an overall 10-year survival rate of 44.4% (p = 0.002 vs non-resected patients). Stage I-II had the best prognosis with a 10-year survival rate of 80% (p = 0.022 vs resected stage III-IV). Patients undergoing primary chemotherapy and/or radiotherapy had the worst prognosis with no survivors at 30 months. In young patients clinical and pathological parameters had almost the same distribution except for sex and histologic type and offered almost the same survival probability as in patients over 40 years of age. When prognostic findings were tested by univariate analysis, only resectability was found to have an independent favourable impact on survival (hazard risk: 7.47; 95% confidence interval: 1.50-37.14).