Continuous epidural opiate analgesia with an implantable, percutaneously refillable pump was induced in 6 patients with chronic pain of malignant origin. The efficacy of this method was compared with that of on-demand bolus-injections of epidural opiate. Side-effects and development of tolerance were not observed during a more than one year period of treatment. Increased daily doses for some days were only necessary in case of additional pain sources, e.g. induced by an intermediate operation. There were no hygienic problems (bacteriologic investigations) or problems due to technique of implantation (localisation of the implant, stability of the fixation, patency of the catheter). Examination of post mortem explanted pumps (determination of the flow rate, inspection for precipitation within the pump, testing of permeability of filters) and catheters (electron microscopy, testing of the material for surface conditions, tensile strength and elongation) as well as histological findings for local compatibility did not reveal adverse reactions after long-term treatment. Indications for this new method of pain treatment were established.