A needle stick injury (NSI) is an accidental skin-penetrating stab wound from a hollow-bore needle containing another person's blood or body fluid, leading to transmission of blood borne infections such as hepatitis B virus, hepatitis C virus and human immunodeficiency virus. Nurses are the core care providers for patients in the hospital and thus have the highest rate of needle stick injury among all the health care workers. This is possibly be due to performance of invasive and non-invasive procedures to the patients besides injection administration more often than any other staff. Aim & Objectives: a) To assess the knowledge of Needle stick injuries (NSI) among nursing staffs, b) To determine the practices of Needdle stick injury prevention (NSI) among nursing staffs of a tertiary care teaching hospital. Materials and Methods: A cross sectional study was conducted by using a structured questionnaire having close ended and multiple choice questions, 10 in knowledge parameters and 15 in practice parameters respectively, designed from previously published literature. Informed verbal consent was taken prior to distribution of the self reporting Questionnaire and 100 nursing staffs were included. Minitab software version 19 was used for data analysis. Duration of study: 1st Jan 2020 to 31st March, 2020 (3 months). Results: Response rate was 80%, Incidence of NSI was 45%, Only 24% of the nurses were aware of the definition of NSI, about 90% of them were aware of the infections transmitted, 85% of them are unaware of 'no-recapping' technique of disposal, 90% of them were aware of standard precautions, Overall knowledge is adequate among 65% nurses. Only 35% nurses reported their NSI after incident, 24% knew post exposure prophylaxis, 98% of the reported NSI incidents NSI were due to recapping of needles. Conclusion: NSIs were highly prevalent among nurses. Injection practices needs improvement. Procedures associated with higher risks of NSIs such as recapping of needles, non-wearing of gloves, improper disposal of sharps and others should be strongly discouraged.