Improved quality of life has long been the goal of cancer treatment, but only recently have investigators begun to include a systematic assessment of quality of life in clinical trials. The major interest for its inclusion in clinical trials has been to assess treatment outcome. An evaluation of the relationship between patient-rated quality of life and survival is reported in a homogeneous sample of patients with advanced metastatic lung cancer participating in a clinical trial. Under the Cox proportional-hazards model (with quality of life, marital status, and their interaction in the model), a statistically significant relationship was observed between initial patient-rated quality of life and subsequent survival. In addition, being married led to a significantly improved survival. These findings suggest that nonmedical factors, such as quality of life assessment and marital status, play a role in survival and that they should be evaluated and described as potential predictors of survival in cancer patients in clinical trials.