Nurses have the highest risk of the sharp injury among all health care providers. We studied the situations and the circumstances surrounding the incident of the injury among nurses in a hospital setting at a medical center with approximately 1,000 beds in southern Taiwan. The study subjects were 117 nurses who have reported to have been sharp-injured. 71.8% of those were the nurses at the N-1 in the clinical ladder system, and 11.1% and 6.8% were the N-2 and the N-3, respectively. Most of the injuries, 66.7%, occurred when she was working alone with instruments, 20.5% when working with another, and 12.8% were caused by another person. 57.3% occurred during the work and 27.4% and 15.4% at the time of discarding and after discarding the instrument, respectively. 49.6%, 29.9% and 16.25 of the injuries occurred in the regular wards, intensive care units and operating rooms, respectively. Nearly three quarters of the injuries in the ward and intensive care units occurred while the nurse was working alone, whereas about half of the incidents in the operating rooms were at the time when they were working with others. These analyses may be of use in the education of the nurses in avoiding the sharp injuries.