A 10 year old male castrated Golden Retriever presented with a history of persistent hypercalcemia. A diagnosis of primary hyperparathyroidism was made on the basis of persistent hypercalcemia, hypophosphatemia, hyposthenuria, increased parathyroid hormone in the presence of hypercalcemia, and identification by cervical ultrasound of a 5mm hypoechoic nodule at the right caudal pole of the thyroid gland. No evidence of a neoplastic process was identified on thoracic radiographs or abdominal ultrasound. Parathyroid-related protein levels were undetectable. Ultrasound-guided ethanol ablation of the abnormal parathyroid gland was performed, and the subsequent decrease in serum ionized calcium levels was documented with serial ionized calcium testing. Hypocalcemia developed four days following treatment and was managed with oral calcium and calcitriol supplementation. Three weeks post-ablation, the patient was normocalcemic.