BACKGROUND Pseudohypoparathyroidism (PHP) is a heterogeneous group of diseases characterized by end organ unresponsiveness to parathormone (PTH), due to receptor or postreceptor defects. The characteristic biochemical disturbances include hypocalcaemia, hyperphosphataemia and high serum parathormone levels. METHODS We present a 17-day-old male baby who was brought to our hospital because of seizures. He was found to have hypocalcaemia, hyperphosphataemia and an elevated serum level of parathyroid hormone. The diagnosis of PHP was based on the elevated serum level of PTH during hypocalcaemia and persistence of normocalcaemia after administering alphacalcidiol with oral calcium. After 4 months of therapy, with tapering of the oral calcium doses, the treatment was discontinued. During the following six months without therapy, the infant did not have seizures and the serum levels of calcium and phosphorus were normal, so we established the final diagnosis of transient neonatal pseudohypoparathyroidism. CONCLUSIONS At the time when the newborn was diagnosed to have PHP, there was no indication whether it was of a permanent or transient form. A considerably lower number of patients have a transitory form of PHP, which is then confirmed in the infant period by a gradual reduction and withdrawal of therapy, with sustaining serum calcium and PTH within normal limits.