The aims of this study were to evaluate the effects of a ketamine/propofol anaesthetic protocol in lions (Panthera leo), and to compare it to two commonly used anaesthetic protocols. Seventeen adult lions were anaesthetised using three different protocols. Group XK (n = 6) was anaesthetised with intramuscular (i.m.) injections of xylazine and ketamine. Group KD (n = 5) was anaesthetised with an i.m. injection of ketamine, followed by an intravenous (i.v.) injection of ketamine of diazepam. Group KP (n = 6) was anaesthetised with an i.m. injection of ketamine followed by an i.v. injection of propofol. There was a significant difference in heart rate (P < 0.0002), which was lowest in group XK and highest in KD. Jaw tone was significantly lower in Group XK (P < 0.05). No undesirable effects were noted following injection of the propofol. Propofol was a suitable and safe drug for maintenance of anaesthesia in adult lions.