A nosocomial infection is an infection in which the clinical, laboratorial and microbiological diagnostic evidence is found after the first 48 hours of admission in a hospital unit. The objectives of this study were to determine the incidence of nosocomial infection in NICU Benha children hospital and to study the risk factors of nosocomial infection. Subjects and Methods: The present study is cross sectional was carried out at Neonatal Intensive Care Unit of Benha Hospital during the period from the start of Jan. 2018 to the end of June 2018 .Data were collected through the following tools: a) Sociographic Data include: Gender, Date of birth, Gestational age in weeks  b) Medical Data include (1) Interventions done to the neonates at the unit: invasive procedure, device exposure and treatments received. (2) Presence of risk factors for infection: weight in grams, Mode of delivery, Presence of congenital anomalies, length of stay.3) Laboratory investigations as count blood cells and blood culture. Results: The percentage of HAI was (23 %). BSI (68.42%) and VAP (31.58%)  There was no statistically significant difference between HAI and Non HAI regarding age on admission, Sex and Mode of delivery. There was statistically significant decrease in G. Age and weight among HAI than Non HAI. There was statistically significant difference between HAI and Non HAI regarding Fate. There was statistically significant increase in Period of stay among HAI than Non HAI. Conclusion: Nosocomial infection in the studied NICU was a relatively high and causes high mortality rates. Low birth weight as well as gestational age and length of stay in hospital were important risk factors in such, infections. However, multi-center studies are needed to confirm these findings.