Objective: This study aimed to assess the knowledge, attitude and practices among health care workers on needle stick injuries. Methods: Hospital based cross-sectional descriptive survey was conducted among HCWs in army force referral and teaching hospital AA, Ethiopia. Pre tested structured questionnaire were administered to health care workers on other hospital in the same professional. Data was entered in to a computer using EPI-3 Info version 5.4 and Data was analyzed using SPSS version 16.0 Result The response rate of the survey was 99.3% and the results showed maximum participant were in the age group of 20-53 years. 97.2% of health care workers were aware of the fact that hepatitis B, hepatitis C, and HIV could transmitted by needle-stick injuries. 82(57.3%) had participated in any training related to infection prevention program. 40(27.9%) and 38(26.6%) were exposed blood /body fluids and had needle stick or sharp injuries in the last one year’s respectively. 104(72.8%) were of the impression that needle should be recapped after used. 24 (16.8%) had been vaccinated against hepatitis B. The prevalence of NSSIs was highest among nurses21 (55.5%) and injuries had occurred while sudden movement of the patient was the most common source of NSSIs. Conclusion; The survey revealed that over all knowledge of health care workers about the risk associated with needle-stick injuries and use of preventive measures was adequate, however, the domains of attitude and practices need to be improved.