Objectives: To understand current medical management practices of hospitals and to investigate the influence of (1)personal characteristics, (2)hospital characteristics, and (3)perceived lack of clinical autonomy on physicians’ self-reported effect of management practices on their medical decisions. Material and Methods: The study is a secondary data analysis from the survey of Prof. Duan-Rung Chen on medical managements. The survey was conducted between late 2004 and early 2005 with structured questionnaires to a population of 16414 physicians practiced in hospitals accredited as district teaching hospitals or higher. SPSS 12.0 was used for descriptive statistics as well as bivariate crosstable analyses and multivariate logistic regression. Results: 2310 questionnaires dispensed through 31 participating hospitals had a response rate of 24.37% and 5519 questionnaires were mailed to individual physicians with a response rate of 13.71%. The overall response rate was 16.86%. Most respondents were male physicians aged between 30 to 49 years and 30.3% of them held an administrative position. Management on quality of medical records was reported by 72.2% of respondents and more than half of them also reported management on the price of one single prescription, the items and amount of medication prescribed, and the length of hospital stay. A lack of freedom in “Use new treatments even when established ones are still available” was reported by 1/3 respondents. 30.1% of respondents stated that the overall effect of medical management practices on their medical decisions was positive. The result of multivariate logistic regression revealed that factors contributing to self-reported positive effect of management practices on medical decisions included: ever served for the National Health Insurance peer-reviewing, clinical working hours less than 40 hours per week, administrative working hours 11-30 hours per week, no inpatients, hospitals providing medical database search resources, perceived balance between effort and reward, perceived appropriateness of performance appraisal, more than 6 physicians to aid in medical decisions within hospital, frequent sharing of experiences between colleagues, and a lower level of lack of clinical autonomy. Conclusions: We suggest that in order to enhance physicians’ positive thinking on management practices to their medical decisions, hospital administrators should assign reasonable job loading, provide resources for medical database search, choose appropriate measures to manage different medical practices, take account of effort-reward balance and performance appraisal, develop an organizational culture of trust, mutual support, and experience sharing, and preserve physicians’ clinical autonomy. We also suggest that future studies may integrate the survey of management practices on hospital level and compare the results with physician level survey to further define the effect of individual management practice on physicians’ medical decisions.