A mixture of medetomidine (50.0 μg/kg, i.m.) and zolazepam–tiletamine (2.0 mg/kg, i.m.) effectively immobilized 16 sun bears (Helacrtos malayanus) for more than 1 hr with good myorelaxation and minimal effects on cardiorespiratory performance during 22 immobilizations. All bears were immobilized once, except for six individuals that were immobilized twice. Atipamezole (250 μg/kg, i.v.) effectively reversed medetomidine-induced sedation and reduced recovery time significantly. Respiratory rates of immobilized bears did not change significantly over time. Rectal body temperature and heart rate decreased significantly after 10 min of immobilization. Hematologic and serum biochemical parameters did not change significantly within 30 min of induction.