Background : Since a Gamma Knife had been installed on December 1997, 405 patients have been treated until December 1999 at department of neurosurgery of Seoul National University hospital. The authors analyzed results of a work to improve satisfaction of Gamma Knife surgery patients and to reduce hospital length of stay. Methods : To understand main discontent of patients, a pre-survey was performed from October 1998 to December 1999 using a questionnaire. By Analyzing 93 questionnaire received from 234 patients, pain on frame application, explanation before surgery, waiting time before surgery, waiting time before medical procedure were main discontent factor and overall satisfaction ratio was 71.0%. To improve satisfaction ratio, several quality improvement activity works were designed and applied to 123 patients during the period between January 2000 and September 2000. The same questionnaire were analyzed. Works to reduce the patient hospital LOS were devised and applied during the same period. Results : The overall satisfaction ratio of Gamma Knife radiosurgery patients was increased to 83.7%(P=0.10). The main factor to improve satisfaction ratio was to reduce waiting time(P=0.05) and improvement of discomfort during the surgery(P=0.06). The average LOS was reduced from 3.1 to 2.7 days(P=0.003). Conclusion : As a result of quality assurance activities, the overall satisfaction ratio of patients was improved and LOS was reduced. The pain during frame application was remained as a main discontent factor and a further study is required to reduce this pain.