Twenty cancer pain patients and 20 matched chronic benign pain patient controls were compared on dimensions of painintensity, affect, expectationsof treatment. Cancer patients perceived their pain as more unpleasant and used words associated with higher sensory intensity than did chronic benign pain patients. Lower levels of emotional distress and higher expectations of relief were reported by cancer patients than by the controls. While affect was unrelated to pain variables for cancer pain patients, affect was consistently related to pain variables and expectations of relief from treatment for chronic benign pain patients.These results suggest that while there is a close interplay between affect and pain perception for chronic benign pain patients, affect and pain perception appear to be distinct for cancer pain patients. These findings imply the necessity for differential treatment of pain complaints in these two patient populations.