One hundred eighty-one female and thirteen postweanling pup southern elephant seals (Mirounga leonina) were sedated using a combination of ketamine hydrochloride and xylazine hydrochloride. Physiological state had a profound effect on response of the animals to sedation. Physiologically stressed postlactation and postpartum cows had significantly longer periods of sedation than pre-molting females or recently weaned pups. Induction time was not affected by physiological status. Dose rates are recommended for elephant seals in various physiological states.