The effects of medetomidine-ketamine and diazepam-ketamine as injectable anesthetic combinations were compared in racing pigeons (Columba livia). Two groups of 6 pigeons of undetermined gender were used. Pigeons in group 1 were anesthetized with medetomidine (125 μg/kg) and ketamine (30 mg/kg) administered intramuscularly. At the first sign of recovery, the medetomidine antagonist atipamezole (65 μg/kg IM) was administered. Pigeons in group 2 were anesthetized with diazepam (2 mg/kg IM) and ketamine (60 mg/kg IM). Response to painful stimuli was recorded for each pigeon in both groups, and changes from baseline in heart and respiratory rates and body temperature were determined. The medetomidine-ketamine combination provided a deeper plane of anesthesia with better analgesia than did diazepam-ketamine, based on significant differences in reflex scores and heart-rate changes after painful stimuli. Recovery was rapid and smooth in pigeons given medetomidine-ketamine, whereas recovery was prolonged in pigeons given diazepam-ketamine. In the clinical study, the level of anesthesia achieved with medetomidine-ketamine was unreliable, with birds exhibiting violent wing flapping. We conclude that further controlled studies must be done in a clinical setting before practical recommendations can be made for using the combination of medetomidine-ketamine for anesthesia of pigeons.