Objectives: To identify barriers to the practice of continuous medical education (CME) by primary health care physicians in Alahsa region, Saudi Arabia. Methods: In this analytic cross-sectional study, 121 participants answered a self-administered questionnaire which measures the level of practice of CME and the prevalence of a number of factors that affect CME practice. The prevalence of the factors that affect CME practice was compared between those who practice CME frequently and those who do not, using appropriate statistical methods. Results: 93 participants (76.9%) practice CME frequently and 28 participants (23.1%) practice CME rarely/never. The factors that have impact on CME practice include the physician's qualification (p-value 0.03), medical knowledge (p-value<0.001), satisfaction with available CME methods (p-value<0.001), CME method preference (pvalue 0.021), belief that group CME activities are provided with poor teaching technique (p-value 0.011), patient load (p-value<0.001) and job satisfaction (p-value 0.014). Conclusion: The most important barriers to practicing CME include lack of post-graduate education, dissatisfaction with the medical information, dissatisfaction with available CME methods, preference for self-taught CME, group CME activities with poor teaching technique, low patient load and job dissatisfaction. The Ministry of health and the Saudi Commission for Health Specialties should work on those factors to improve the practice of continuous medical education by primary health care physicians.