Background : Neonatal sepsis continues to be a major cause of morbidity and mortality in the neonatal period . Aim of the work : The aim of this study was to determine the microbiological pattern of bacterial infection in Kasr El –Aini neonatal intensive care unit on admission and before any interference and to determine the incidence of early and late onset sepsis.Study design : This study was a prospective analytic study. Patients & Methods : All high risk neonates whether preterm or fullterm admitted to kasr El- Aini neonatal intensive care unit for 6 months during the period from 1/3/2002 to 30/9/2002 were included in the study.Our exclusion criteria was babies with congenital anomalies , infant of diabetic mother, infant died within 24 h. Included neonates were subjected to lab. Studies as CBC, CRP, ITratio, superficial cultures in the form of ear & throat swabs and deep culture in the form of blood culture. We defined neonatal sepsis by +ve blood culture. Results : 70 neonates out of 101 neonates included in the study developed sepsis (69.3 %). The incidence of early onset sepsis (49.5 %)_ was much higher than late onset sepsis . the highest incidence of sepsis was in the gestational age group 30<32 weeks and the weight group 1500<2500 grams. Clinical signs and lab. Investigation revealed no significance in relation to sepsis. The most prevalent organism recovered from blood culture was Klebsiella (40%), followed by CONS (20%), Staph aureus (15.7%) and Enterobacter (15.7%). Superficial swabs were of limited value in diagnosis of neonatal sepsis. Results of throat swabs were more significant than ear swabs with higher matching with blood culture (21.4% in contrast to 8.5% for ear swabs). Mortality among septic neonates was 44.2% & among non septic neonates was 25.8 %. Conclusion: Incidence of sepsis is still very high in our unit (69.3%) Early onset sepsis was much higher than late onset sepsis. Superficial swabs are of limited value in diagnosis of neonatal sepsis .Blood culture. Is still the gold standard for the diagnosis of neonatal sepsis.