About 10% of patients with cancer pain do not obtain pain relief or experience unacceptable side effects with systemic opioids. In some cases a change of the route of administration can improve the balance of analgesia and adverse effects. In this paper the use of spinal opioids in such patients is discussed from various aspects: patient selection, epidural vs intrathecal administration, dosage, association with local anaesthetic agents, dosage conversion systems (for the change from systemic administration) and home use. The main problems involved are dealt with an attempt to find how to use the drugs and techniques involved to the best possible advantage.