Prevention of needle stick injuries (NSI) remained a challenge to the health care workers throughout the world. In Malaysia, efforts to prevent NSI among health care workers has been one ofthe emphases as these injuries may cause serious and potential fatal infections such as Hepatitis B, Hepatitis C and HIV. This retrospective cohort study was done to determine factors related to prevalence of NSI among health care workers in government health facilities in Negeri Sembilan that were reported from 2001 until 2003. There were 101 cases of NSI reported affecting various categories of health staff and also paramedical trainees and medical students. The NSI occurs mostly in females (72.35%), age 30 years or less (73.2%), and trainees of medical or paramedical courses (45.4%). Other characteristics found are as follows: cases had attended SP courses (60.4%) , had less than 5 years in service (78.1%) and mostly never had NSI before (93.1%), However 84.2% of N SI among the respondents that have good and very good knowledge levels on NSI prevention. It is recommended that follow-up or audit on the practice of the Standard Precautions (SP) should be implemented following the training of staff. It is also important that medical trainees or paramedical students be adequately trained on SP before entering the clinical environment.