Ten cancer patients treated with stable doses of epidural opioids were tested for postural stability. The postural stability was measured using a quantitative Romberg's test, performed on a computerized force-plate system. Sway tendencies in the sagittal and the transverse directions were recorded. The postural stability of the patients was compared with values obtained from healthy controls. Comparing the cancer patients with the controls, postural stability in eight out of ten patients was intact. The study suggests that long-term epidural opioid treatment has little influence on the patient's ability to stand safely.