Providing adequate perioperative analgesia and sedation while minimizing respiratory depression remains an elusive goal. The past year has witnessed continued evaluation of the respiratory effects of agonist and antagonist drugs, administered by various routes, individually as well as in combination. Among the more interesting findings are possible explanations for respiratory insufficiency during spinal anesthesia with sedation, and for acute respiratory depression following lumbar epidural administration of lipid-soluble opioids. The roles of nalbuphine and tramadol in providing analgesia with limited respiratory depression, as well as that of flumazenil and the β-carboline derivative, ZK-93426, in treating ventilatory depression that is induced by benzodiazepines, continue to be defined. Finally, refined methods such as the ventilatory response ratio and step hypoxic challenges, are beginning to provide new information on respiratory pharmacology.