Currently in healthcare organizations paper-based patient record management faces many challenges. Most countries are promoting the full implementation of electronic medical records in every hospital. Medical environments change frequently and dramatically, which makes full acceptance of electronic medical records (EMR) by physicians an important issue. This empirical study combines the theory on reasoned action (TRA) and information technology acceptance model (TAM) resulted in a modified TAM to find what critical factors influence the acceptance behavior of EMR by physicians. To test these hypotheses, this study administered a cross-sectional mailed questionnaire survey during the period of three months in 2012. The survey was deployed to1000 physicians randomly from the estimated total 2000 physicians of 50 regional acute hospitals (more than 300 beds) in Taiwan currently. From these, 252effective responses were received, resulting in a net response rate of 25%. These research findings indicate that four variables significantly positively impact the intention to adopt EMR. Among these, attitude has the most significant positive impact on adoption intentions. Moreover, it shows that the professional autonomy might play an important role to moderate the attitude with significant statistics. These results maintain enough explanatory power (R2 =78.4%) to help explain the attitudes and intentions of physicians in adopting electronic medical record information systems. Our analysis revealed the importance of the perception usefulness which moderated by professional autonomy and pragmatism by physicians for their adoption electronic medical record systems in clinical practices