Background and Aim: Evidence Based Medicine (EBM) is the explicit use of current best evidence in making decisions about the care of individual patients. Hospital information system (HIS) can act as a bridge between medical data and medical knowledge through merging of patient's data, individual clinical knowledge and external evidences .The aim of this research was to determine the Capability to establish EBM by HIS.

 Materials and Methods: This descriptive cross-sectional study was carried out on HISs of 30 hospitals from March to October 2011. Data were collected using a researcher- constructed checklist including applicant’s background information as well as information based on research objectives. Validity of the checklist were assessed by the qualified specialists and then the data were analyzed using descriptive statistics and SPSS software.

 Results: HISs lacked the essential components for providing access to CDSS, Reference databases and internet-based health information in 19, 16 and 20 hospitals were 63.3%, 53.3% and 66.7%, respectively. Twenty-two hospitals (70%) had more than two-thirds of the essential components to access clinical and administrative data repositories; 23 hospitals (76.7%) had at least one essential component to access contextual and case specific information.

 Conclusion: The Capability of HIS is better in order to place EBM in having access to the clinical and administrator data repositories; while it needs more attention in other areas.