It has been suggested that marital status and social support are associated with survival in cases of lung cancer, and that such an association may be mediated by several factors. In this prospective cohort study, we investigated the effect of marital status and social support on survival after curative resection for non-small cell lung carcinoma (NSCLC) in Japan. From June 1996 to April 1999, a total of 238 patients with resectable NSCLC were enrolled. Marital status and social support were assessed. The presence and absence of confidants and the satisfaction level with the confidants were used as factors reflecting social support. During the follow-up period, 57 deaths from all causes were identified through January 2004. For the statistical analysis, Cox proportional hazards regression analyses were used. With regard to marital status, the multivariable adjusted hazard ratio (HR) of unmarried patients versus married patients was 0.8 (95% confidence interval, 0.3-1.8) (P-value=0.53) after controlling for potential confounding factors, including age, sex, occasion of cancer diagnosis, pathological stage, smoking status, smoking status after surgery and serum albumin level. Similarly, the multivariable adjusted HR of patients without confidants versus those with confidants was 1.0 (0.5-2.2) (P-value=0.90), whereas the multivariable adjusted HR of the dissatisfied-with-confidants group versus the satisfied-with-confidants group was 0.7 (0.4-1.3) (P-value=0.28). The present data do not support the hypothesis that marital status and social support are associated with survival in NSCLC.