A 16 year old patient with the typical clinical signs of Albright's hereditary dystrophia developed series of epileptic seizures with loss of consciousness, tonic muscle contractions and bite of the tongue. After termination of the seizures there was coma without focal neurological signs. CT scan revealed diffuse brain edema. Electroencephalographic studies showed generalized slowing. In laboratory tests the only abnormalities were marked hypocalcemia (1.15 mmol/l) and hyperphosphatemia. Blood parathyroid hormone (PTH) was elevated. PTH-Test confirmed the diagnosis of pseudohypoparathyroidism. The patient was treated with calcium and 1,25-dihydroxy-cholecalciferol. After few days the severe encephalopathy, CT and electroencephalographic changes were completely reversible. Hereditary disturbances of the parathyroid hormone metabolism are rare diseases. Hypocalcemia must be included into the differential diagnosis of seizures and brain edema to avoid invasive diagnostic and irrational treatment.