Four patients developed acute arthritis following parathyroidectomy over a 3 year period in two general surgical practices. The diagnosis of pseudogout was made by clinical presentation, radiologic findings and demonstration of synovial fluid crystals exhibiting weakly positive birefringence. Rapid resolution of clinical arthritis followed joint aspiration and administration of anti-inflammatory agents in all four patients. Patients with hypercalcemia have a high incidence of calcium pyrophosphate dihydrate crystal deposition into joints. Rapid drops in serum calcium levels can cause shedding of these crystals into synovial fluid which may precipitate acute attacks of pseudogout. Because the relative hypocalcemia following parathyroidectomy provides a good stimulus for crystal shedding, it follows that hypercalcemic patients undergoing parathyroidectomy should experience a high incidence of acute pseudogout. Although this entity has been described before, its occurrence is not widely recognized in clinical practice. It is proposed that these four cases observed over a 3 year period indicate that pseudogout following parathyroidectomy occurs more commonly than previously recognized.