This chapter reviews the use of regional anesthesia techniques in obese patients. The most extensive experience with regional anesthetic techniques in obese patients is with neuraxial anesthesia. Obese patients require less local anesthetic than their normal counterparts to achieve a similar sensory level. For a lumbar approach for either an epidural or spinal anesthetic, a cooperative patient can be asked to identify the "midpoint of your body". The incidence of complications with epidural anesthesia increases with increasing weight. As with epidural anesthesia, obesity is an important factor influencing spinal anesthesia. Neuraxial anesthesia is often used in combination with general anesthesia during surgery to reduce the amount of inhalational and intravenous agents. All peripheral nerve blocks were performed using a nerve stimulator technique. Overweight and obese patients should not be excluded from undergoing regional anesthesia in the ambulatory setting.