Failed Back Surgery Syndrome (FBSS) is a multidimensional painful condition and its treatment remains a challenge for the surgeons. Prolonged intrathecal infusion of opiates for treatment of noncancer pain also remains a controversial issue. The authors present a prospective study about the long-term treatment of 30 patients with nonmalignant pain treated with intrathecal infusion of morphine from February, 1996 to May, 2004. Self-administration pumps were implanted in 18 patients and constant-flow pumps in 12. The mean intensity of pain reduced from 9.5 to 4.6 according to the visual analogue scale (p < 0.001); the mean daily dose of morphine necessary for pain control became constant after the sixth month of treatment. No difference was observed in the results between patients treated with bolus or constant infusion. Side effects were more frequent at the beginning and became tolerable after the first month of treatment. There was improvement of the quality of life measured by SF-36 (30.8-49.6) and in all dimensions of the Treatment of Pain Survey, except for working capacity. The follow-up period ranged from 18 to 98 months (mean = 46.7 months). It was concluded that intrathecal infusion of morphine is a useful and safe tool for long-term treatment of chronic nonmalignant pain.