Pseudohypoparathyroidism (PHP) is characterized by unresponsiveness of target tissues to the biological actions of the parathyroid hormone (PTH), with resulting hypocalcemia and hyperphosphatemia, despite the elevated serum levels of PTH. PHP is divided into types Ia, b, c and II, depending on the presence of Albright's hereditary osteodystrophy (AHO), defective urinary excretion of phosphate (U-P) and response in urinary excretion of cyclic adenosine monophosphate (U-cAMP) after the administration of exogenous PTH. Patients with PHP might exhibit various manifestations of neuropsychic disturbances. We present two boys, aged 14 and 16 years, both with paresthesia, anxiety and epilepsy; the former patient also suffered from mild mental retardation. In both patients, hypocalcemia and hyperphosphatemia together with increased serum levels of PTH suggested the diagnosis of PHP. After administration of exogenous PTH (Ellsworth-Howard test), there was a drop in U-P in both patients, while U-cAMP was decreased in the first patient and increased in the second one, thus confirming the diagnoses of PHP Ia and II, respectively. Neuropsychic disturbances and epilepsy resolved completely in both patients after treatment with calcium and dihydrotachysterol. Evaluation of calcemia and phosphatemia should be mandatory in all patients with neuropsychic disorders. Ellsworth-Howard test remains a useful tool in the differential diagnosis of PHP.