Background and Objective: COVID-19 infection among health personnel is a major problem and has severe impacts. This cross-sectional survey design aimed at the factors influencing the practice of COVID-19 prevention among health personnel. Methods: The sample consisted of health personnel working in the emergency department, in-patient wards, and out-patient department in Rajavithi hospitals (n=60) selected using a purposive sampling method. Data were collected using questionnaires which were validated by 5 experts and had a content validity index of 0.83. The reliability of the questionnaires was 0.91. Data were analyzed using descriptive statistics and multiple regression. Results: The results of this study revealed that subjects had good attitudes toward behaviors, subjective norms, perceived behavioral control, and intention for COVID-19 infection prevention. In addition, perceived behavioral control was the only factor that statistically predicted practice intention for COVID-19 infection prevention and may explain 25.6% of the variability of intention (p < .001). Conclusions: Based on the Results of this study, it is suggested that relevant authorities including wards and infection control units should support perceived behavioral control among registered nurses to encourage COVID-19 infection prevention intention for COVID-19 infection prevention.