Objective To evaluate the effects of medetomidine, midazolam and ketamine (MMK) in captive gorillas after premedication with oral zuclopenthixol. Study design Case series. Animals Six gorillas, two males and four females, aged 9–52 years and weighing 63–155 kg. Methods The gorillas were given zuclopenthixol dihydrochloride 0.2 ± 0.05 mg kg)1 per os twice daily for 3 days for premedication. On the day of anaesthesia the dose of zuclopenthixol was increased to 0.27 mg kg)1 and given once early in the morning. Anaesthesia was induced with medetomidine 0.04 ± 0.004 mg kg)1, midazolam 0.048 ± 0.003 mg kg)1 and ketamine 4.9 ± 0.4 mg kg)1 intramuscularly (IM). Upon recumbency, the trachea was intubated and anaesthesia was maintained on 1–2% isoflurane in oxygen. Physiological parameters were monitored every 10 minutes and arterial blood gas analysis was performed once 30–50 minutes after initial darting. At the end of the procedure, 42–115 minutes after initial darting, immobilisation was antagonized with atipamezole 0.21 ± 0.03 mg kg)1 and sarmazenil 5 ± 0.4 lg kg)1 IM. Results Recumbency was reached within 10 minutes in five out of six animals. One animal required two additional darts before intubation was feasible. Heart rate ranged from 60 to 85 beats minute)1, respiratory rate from 17 to 46 breaths minute)1 and temperature from 36.9 to 38.3 �C. No spontaneous recoveries were observed and anaesthetic level was stable. Blood gas analyses revealed mild respiratory acidosis, and mean PaO2 was 24.87 ± 17.16 kPa (187 ± 129 mmHg) with all values being above 13.4 kPa (101 mmHg). Recovery was smooth and gorillas were sitting within 25 minutes. Conclusion and clinical relevance The drug combination proved to be effective in anaesthetizing captive gorillas of various ages and both sexes, with minimal cardio-respiratory changes.