Although there is a need for systematic research on the psychosocial issues faced by lung cancer patients, there have been few studies in this area. The objective of the present study was to investigate potential predictors of psychological distress among ambulatory lung cancer patients. The variables examined included the patients' characteristics, coping responses, and social support factors. Lung cancer patients completed the Profile of Mood States (POMS) and the Mental Adjustment to Cancer scale (MAC scale), and information pertaining to demographic variables and social support factors was obtained from them at a structured interview. Evaluable data were obtained from 87 patients. The results of multiple regression analysis indicated that female gender, living alone, no children in the role of confidant, nurses as confidants, and helplessness/hopelessness as a coping style were predictive for psychological distress. Information on patients' demographic variables and psychosocial correlates of psychological distress may later be useful in developing interventions to facilitate their adjustment to lung cancer.