For pain relief after thoracotomy, intercostal nerve block with etidocaine 1% and bupivacaine 0.5%, both containing adrenaline 5 mug/ml, was used. Duration of skin analgesia for sharp pain was around 11 hours for both solutions. Post-operative pain was noted 6 and 5 hours after injection for etidocaine and bupivacaine respectively. No pathological changes in acid-base balance or ventilation were observed. Peak expiratory flow decreased to 35-40% of the pre-operative values and remained at this level for about 12 hours. Arterial and venous blood levels of the local anaesthetics were low and no signs of toxicity were noted. All patients experienced a certain pain relief from the blocks. Because of shoulder pain in some patients intercostal nerve block alone does not seem to be a perfect post-operative method for pain relief after thoracotomies.