Objectives: To establish a research framework and to identify the critical factors affecting HIS (Hospital Information Systems) performance evaluation. Methods: Data was collected through a self-administered questionnaire survey. The target population was CEOs of 120 regional hospitals and medical centers in Taiwan. The questionnaires were mailed to the CEOs directly and their response rate was 35%. The results of the surveygoodness of fit test indicate that the accreditation classes of the returned sample hospitals have no significant difference from the target population. Results: Seven factors signficantly affected the results of Information Technology (IT) performance evaluation; they are government policy and competitors of the environmental dimension, vendors' characteristics, previous business experience in hospitals, and costs of the IT and vendors' technical ability, hospitals' structure and top managements' attitude, and expectations of the organization on HIS. The regression model indicates that at a 5% level of significance, only the environment and the organizational dimensions are statistically significant to HIS performance. Conclusions: "Hospitals' structure and top managements' attitude" is the most important factor affecting the evaluation of results of the HIS performance. The second most important factor is "government policy".