The literature suggests that the sex of patients is an important factor in understanding how they are treated by health care professionals and how they adapt to their symptoms. In two groups of patients with chronic pain (n = 428 non-cancer (Study 1) and n = 143 cancer-related (Study 2)), men and women were compared on medications prescribed, treatment history, and coping and adaptation. In Study 1 with the non-cancer pain patients, there were no significant differences between the sexes in past treatments, current analgesic use, pain, or disability. Women were significantly more depressed and were more likely to receive antidepressants than men. Subgrouping patients on the basis of pain-adaptation responses yielded groups with distinct psychosocial and behavioral characteristics. In Study 2 with the cancer pain patients, men and women did not show significant differences on any variables. Consistent with the results of Study 1, however, psychological subgroups differed significantly in pain severity, mood and disability regardless of sex. The results of both studies suggest that the role of patients' sex in chronic pain may be less important than their psychosocial and behavioral responses. Thus, it appears that knowing the psychological characteristics of patients may be more important than their sex.