Neonatal sepsis is a frequent and important cause of morbidity and mortality in the neonatal period. This study was undertaken to observe the 55 cases of proven neonatal sepsis among 6,717 newborn infants under 4 weeks of age, admitted to the nursery of Yeungnam University Hospital from May 1, 1983 to April 30, 1988. We observed following results : 1. The morbidity rate of male(1.12%) was higher than that of female(0.44%) significantly (p<0.05). 2. The morbidity rate of prematurity(2.65%) was higher than that of full term(0.76%) significantly (p<0.05). 3. The incidence of perinatal obstetric complications in early onset neonatal sepsis was higher than that of late onset neonatal sepsis (38.5% vs 10.3%, p<0.05). 4. The common clinical manifestations were poor feeding(52.7%), jaundice(45.5%), diarrhea(30.9%) and irritability (30.9%). 5. Among the causative organisms, gram positive organisms were predominated and Staphylococcus epidermidis was the most common organism. There was no difference in the causative organisms between early onset and late onset sepsis.