Background: Building a knowledge sharing culture is necessary for staff nurses to enhance their organizational citizenship behaviors. Aim of study: Was to assess knowledge sharing and its relation to organizational citizenship behaviors as perceived by staff nurses. Research design: A descriptive correlational design was used. Setting: The study was conducted at all critical care units in Benha University Hospital. Subject: A convenience sample consisted of (200) staff nurses who are responsible for providing direct nursing care activities to patients in the above-mentioned study setting and have at least three years of job experience. Tools of data collection: Two tools were used for data collection; first tool: knowledge sharing questionnaire, and the second tool: organizational citizenship behaviors questionnaire. Results: 89.5% of staff nurses had a high perception level of knowledge sharing and 87.0% had high level of organizational citizenship behaviors. Conclusion: There was a highly statistically significant correlation between knowledge sharing and organizational citizenship behaviors. Recommendations: Enhance staff nurses' awareness of knowledge sharing and organizational citizenship behaviors by conducting educational programs, workshops, and conferences to improve outcomes related to patients and the organization.