A 3-year-old Thoroughbred colt was presented to the University Veterinary Centre Camden for evaluation of ataxia. The horse was anaesthetised to facilitate cervical radiography and myelographic examination of the spinal cord. Recovery from anaesthesia was uneventful. Five days after general anaesthesia the horse re-presented with pleuropneumonia. It was euthanased 24 hours after presentation on humane grounds. Necropsy revealed severe tracheal erosion over the middle third of the ventral surface of the trachea, pleuropneumonia and narrowing of the cervical cord between C4 and C6. It is postulated that extension and flexion of the neck during myelography resulted in movement of the endotracheal tube cuff, causing the tracheal lesion and predisposing the colt to pleuropneumonia. Severe tracheal lesions and pleuropneumonia have not been reported as sequela of equine myelography, and should be considered as possible complications following repeated cervical manipulation during myelography in the horse.