Purpose : This study aimed to identify the factors influencing occupational health preventive behaviors among workers in small-sized workplaces, which are particularly vulnerable to infectious diseases, based on the Health Belief Model during the COVID-19 pandemic. Methods : A descriptive cross-sectional survey was conducted from July to September 2020, involving 268 workers from microenterprises with under 50 employees. The structured questionnaire included items on general characteristics and key components of the Health Belief Model. Results : The average score for COVID-19 workplace preventive behaviors was 2.87 out of 4 points (15 items). Significant predictors of infection prevention behaviors included employment type (β=-0.184, p=.008), shift work (β=0.137, p=.035), presence of response protocols (β=0.135, p=.023), perceived benefits (β=.064, p=.009), and perceived barriers (β=-0.161, p=.008). Conclusion : To enhance infectious disease prevention in Small-sized workplaces, it is essential to establish and communicate systematic response guidelines, implement educational programs emphasizing the benefits of preventive behaviors, and foster a supportive workplace culture that minimizes organizational barriers to preventive practice implementation.