Of the various agents which have been employed for sedation in patients undergoing electrocardioversion, diazepam has had the most extensive use. However, this agent possesses several disadvantages including pain and venous complications at the site of injection and a lower incidence of amnesia. Midazolam, a benzodiazepine derivative, is being increasingly used in general and local anesthesia as well as for procedures requiring conscious sedation, eg, endoscopy. We used intravenous midazolam for conscious sedation in 12 patients undergoing a total of 17 cardioversions. All of the patients experienced amnesia for the procedure and manifested no significant adverse effects. However, serious respiratory failure may occur when intravenous midazolam is used in patients with COPD, debilitated patients, or when the drug is injected rapidly. The use of midazolam should therefore be confined to areas that are able to deal with cardiorespiratory complications. Using guidelines and precautions described here, we encountered no major complications. We conclude that midazolam offers a safe and effective alternative to other agents for conscious sedation in patients undergoing electrocardioversion.