The aim of the present study was to assess the prevalence of needle stick injuries (NSIS) among nurses in Riyadh, Saudi Arabia. Materials and methods: Through cross sectional approach a self-administered questionnaire was distributed to 400 active-duty nurses selected randomly. In addition to the socioeconomic characteristics, the questionnaire inquired about the number of NSIs ever experienced, activities and department of employment at the time of injury and nurses' perception of causes of NSIs. Results: Out of 324 respondents, 113 [34.9%] were males, 211 [65.1%] females, 107 [33%] Arabs, 217 [67%] non-Arabs. The mean age was 36.7 6.9 years. NSIS were experienced by 147 [45.4%] nurses, 51.7% of females, 33.6% of males, 58% of single nurses, and 43.1% of married ones. Nurses in ICU, emergency and surgery departments reported the highest rates [62.5%, 56.7% and 55% respectively]. Activities at time of injuries included I. V. line related occasions [20.0%], recapping [24.9%] and disposal [20.4%]. Around three fourths of the sample [74.8%] perceived haste as cause of NSIS, followed by tension [37.5%] and lack of experience [25.7%]. Post exposure, 29.5% used local wound care and 3.4% received HB vaccine and HBIG. Recommendations: Health education programs addressing the use of needles with safety features and post exposure infection control procedures should to be conducted in health care facilities. Key words: Needle stick, occupational risk, nursing hazards.