Title: Knowledge and practices regarding Nosocomial infection among nurses in hospitals of Islamabad. Objectives: Objectives of the study were to determine the level of knowledge and practices regarding Nosocomial infection among nurses working in public and private hospitals of Islamabad and to determine the factors associated with knowledge and practices among these nurses. Design: A cross sectional study based on self-administered questionnaire was ducted. Setting: Study was carried out in public and private tertiary teaching hospitals in Islamabad. Study Participants: A sample of 356 nurses including 185 from public hospital and 171 from private hospital through stratified random sampling proportion to size for collecting information regarding knowledge and practices about Nosocomial infection was selected. Main outcome measures of the study were good and bad knowledge and practices regarding Nosocomial infection. Results: A total sample size was 356 participants was studied where 185(51%) nurses from public hospital and 171(48%) from private hospitals were included. Most of the participants, 212 (59.6%) were of age between 20-29 years. Among the participants 221(62.1%) were females and 135 (37.9%) were male staff. Regarding knowledge level, 194(54.5%) participants had good knowledge about Nosocomial infection and as far as practice is concerned, 204(45.5%) of the participants had good practices regarding Nosocomial infection. Conclusion: Overall, the knowledge and practices of the nursing staff was good. Based on facility, knowledge of the private hospital was better as compare to knowledge of the participants of public hospital however, practice of the participants from public hospital was better as compare to the practice of the participants from private hospital.