Water clear cell hyperplasia (WCCH) and water clear cell adenomas (WCCA) of the parathyroid glands are rare causes of primary hyperparathyroidism. We report in this series one case of WCCH and two cases of WCCA representing 0.3% of patients with primary hyperparathyroidism presenting to our institution. Increased parathyroid cellular water content was responsible for relatively larger parathyroid gland sizes. However, this was not associated with higher biochemical markers or more severe clinical presentations. Histological distinction between WCCH and WCCA is difficult but important since patients with WCCH who have had a parathyroidectomy via a unilateral neck exploration may carry an increased risk of future disease recurrence.