A nationwide follow-up survey was undertaken to study the use of extradural and intrathecal opioids in the management of pain, to estimate the incidence of delayed ventilatory depression and to study post-injection surveillance routines. A questionnaire was sent to all 93 anaesthetic departments in Sweden; 96% responded. The major indication for using extradural opioids was the treatment of postoperative, traumatic and cancer pain. During 1984 over 14000 patients received extradural, and over 1100 patients intrathecal, opioids. Morphine was the predominant opioid for extradural administration and was used in 96% of patients. Extradural opioid analgesia constitutes about 25% of all extradural blocks performed in Sweden. Pruritus and urinary retention were considered as minor problems; however, the risk was considerably higher after intrathecal morphine. The incidence of delayed ventilatory depression was about 1: 1100 (0.09%) following extradural morphine and 1:275 (0.36%) following intrathecal morphine. Risk factors for delayed ventilatory depression are discussed. Administration of extradural morphine for postoperative pain relief in patients undergoing major surgery is considered a high benefit-low risk technique by most Swedish anaesthetists. The results of the present nationwide survey suggests that, following extradural morphine, surveillance of patients for smore than 12 h appears unnecessary.