Background: Nosocomial pneumonia is the most frequent cause of hospital acquired infections in the Intensive Care Unit (ICU). Objective: This study aimed to study Hospital-Acquired Pneumonia (HAP) and Ventilator-Associated Pneumonia (VAP) regarding clinical characteristics, risk factors, main bacterial causes and their antimicrobial susceptibility. Methodology: Sputum and endotracheal aspirates samples were collected from hospitalized adults who developed nosocomial pneumonia at the Respiratory Intensive Care Unit (RICU) of the Chest Department of Assiut University Hospital. Bacterial causes were isolated by culture and identified conventionally. Antibiotic susceptibility was done for isolated micro organisms by disc diffusion method. Results: This study included one hundred adult patients. Fifty four of the patients were males. HAP was accounted for 42% and VAP 58%. Klebsiella species and methicillin-resistant Staph aureus (MRSA) were the predominant isolated pathogens. Conclusion: Nosocomial Pneumonia, mainly VAP, is very important hospital-acquired infection which causes high mortality rate in the RICU. Identification of the causative pathogens and their antibiotic sensitivity patterns can help physicians choose appropriate antibiotics to improve the outcome.