This study investigated the relationship between prognosis (estimated by histopathologic indicators) in cutaneous malignant melanoma and a comprehensive set of physical risk, demographic, psychosocial, and situational variables. These variables were derived from the medical examination, the pathology report, psychosocial self-report measures, and an hour-long videotaped interview with 59 patients from two melanoma clinics in San Francisco. Variables significantly correlated with tumor thickness were: darker skin/hair/eye coloring, longer patient delay in seeking medical attention, two correlated dimensions within an operationally defined 'Type C' constellation of characteristics, two character style measures, and less previous knowledge of melanoma and understanding of its treatment. Of these variables, delay was the most significant in a hierarchical multiple regression analysis in which tumor thickness was the dependent variable. Associations between tumor thickness and psychosocial measures of Type C were considerably stronger and more significant for subjects less than age 55, suggesting that the role of behavioral and psychosocial factors in the course of malignant melanoma is more potent for younger than for older subjects.