Xylazine Hcl was generally used in veterinary medicine for its sedative and moderate analgesic effect. This experimental study was undertaken to determine the effect of repeated intravenous (IV) administration of xylazine on sedation and analgesia as well as cardiac arrhythmia using ECG in donkeys. Three repeated injections of xylazine (0.5 mg/kg) with 10 minute interval were injected IV in six healthy adult donkeys. Sedation score, analgesic score, heart rate (HR), respiratory rate, rectal temperature and ECG parameters were recorded before and after 2, 5 and 10 minutes from injection for each injection and then at 5 minutes intervals until complete recovery from sedation and the normal ECG was recorded. Deep sedation was obtained 5 minutes after the second injection in all donkeys, and the length of sedation lasted 71 ± 6 minutes. The deep analgesia was obtained 5 minutes after the third injection in all donkeys, and the length of analgesia lasted 62 ± 5 minutes. There was a highly significant decrease in HR after the third injection (P < 0.01). Normal HR was obtained in all donkeys after 75 ± 10 minutes of the third injection. Cardiac arrhythmia as atrial fibrillation and AV block were recorded after second and third injection but this arrhythmia was transient. We can conclude that repeated injection of xylazine Hcl give acceptable results either for sedation or ECG parameters in donkeys.