The Formosan serow (Capricornis swinhoei) is a rare endemic species found in Taiwan. Few studies, including studies on anesthetic protocols, have been conducted on this species. This study evaluates the anesthetic effectiveness of intramuscular xylazine–ketamine and dexmedetomidine–ketamine on captive Formosan serows. Fifty-seven anesthetic events were performed on 22 adults using a combination of xylazine (2.6 ± 0.5 mg/kg) and ketamine (3.7 ± 1.0 mg/kg). Forty-eight anesthetic events were performed on 29 adults using a combination of dexmedetomidine (33.9 ± 4.3 μg/kg) and ketamine (3.4 ± 0.4 mg/kg). Xylazine–ketamine anesthesia was antagonized with tolazoline (3.3 ± 0.8 mg/kg). Dexmedetomidine–ketamine anesthesia was antagonized with atipamezole (272.8 ± 78.2 μg/kg). Both drug combinations showed smooth anesthetic and recovery processes without statistical differences in respiratory rate, heart rate, rectal temperature and hemoglobin oxygen saturation. Dexmedetomidine–ketamine reversed by atipamezole showed a significantly shorter recovery time (1.8 ± 2.3 min) than xylazine–ketamine reversed by tolazoline (4.5 ± 1.7 min) (P < 0.05). Both anesthetic protocols indicated safe and reliable immobilization whereas atipamezole provided better reversal.