The increasing incidence of lung cancer in women and their supposed survival advantage over men requires clarification of the significance of sex. Age, stage, histologic features, differentiation grade, and Ki-67 index were assessed in 405 surgically resected non-small cell lung cancers (NSCLCs) using a standardized tissue microarray platform. Women were associated with well/moderate tumor differentiation, a Ki-67 index of 3% or less, and adenocarcinoma histologic features. Female sex predicted increased survival time only by univariate analysis. Stratified by sex, increased survival was noted for women older than 64 years, with a tumor at postsurgical International Union Against Cancer stage I, with adenocarcinoma histologic features, with well- or moderately differentiated tumors, or with a Ki-67 index of 3% or less. Sex is not an independent prognostic parameter for patients with surgically resected NSCLC. Sex-linked differences are associated with other factors, thus simulating a prognostic impact of sex. This study elucidates sex-specific interactions between patient and tumor characteristics, which are pivotal toward improving prognostic accuracy, individualized therapies, and screening efforts.