A hospital case-control study in Isfahan, Islamic Republic of Iran, compared the psychological features of 200 patients with low-back pain with 350 matched controls. The control group scored lower than patients in all dimensions of the Symptom Checklist-90 checklist. Female patients were more psychologically affected by low-back pain than males. In both groups, grudge, general complaints, anxiety, depression, obsessive-compulsive behaviours, somatization and phobia varied with level of education. Patients' levels of depression and anxiety were related to occupational background. Longer duration of illness was accompanied by higher levels of anxiety, depression, obsessive-compulsive behaviours and somatization.