Early hypocalcemia, which occurs in the first 48 hours of birth, is an important electrolyte disorder of neonatal period. Delay or failure of its diagnosis may result in dangerous and irreversible complications such as seizure and death.

This prospective- cross sectional study had designed to evaluate prevalence, etiology and clinical presentation of early neonatal hypocalcemia in Fatemieh and Ekbatan hospitals of Hamedan in 2002. This study was done by preparation of the checklist of necessary information getting from the patients file and then analysis the data with SPSS10 software.

25 cases out of 180 neonates of less than 48hours life had hypocalcemia, 17 cases of them experienced asphyxia, 7 cases were premature and 1 case was infantof a diabetic mother. Clinical presentation of early hypocalcaemia were: seizure , decreased neonatal reflexes and excitability.

          Results showed that early neonatal hypocalcemia was relatively frequent in our study group and its clinical presentation was similar to other studies which were carried out in other countries, but the first cause of this disorder in our study was asphyxia while in other countries it was prematurity.