BACKGROUND: Exposure to the coronavirus (COVID-19) in industrial workplaces has caused concerns all over the world. Implementation of prevention measures is the best solution for protection of workers’ health. OBJECTIVE: The present study investigated prevention measures and risk factors for the COVID-19 infection in Iranian small, medium, and large industries. METHODS: This study was conducted on 349 occupational health, safety, and environment professionals working in different industries. Data was collected using a checklist of prevention measures for COVID-19 and a questionnaire of risk factors for the infection. RESULTS: The results demonstrated that 32.60%of industries reported positive cases of COVID-19. The mean of prevention measures in all the dimensions, except use of personal protective equipment (PPE), was in favorable status. Among prevention measures against COVID-19, the dimensions of education, engineering controls, use of PPE, use of hand washing soap and disinfectant, and physical distance were not significantly different among small, medium, and large industries. However, administrative controls were statistically lower in small and medium industries compared to the large industries. Moreover, screening was statistically lower in small industries than in large industries. The mean risk factors of ventilation, use of common tools and equipment, and physical distance as well as total risk factors were not statistically different among different industries. CONCLUSION: Workers are at risk of COVID-19 infection. The risk factors of ventilation, sharing tools and equipment, and physical distance are critical in classification of risk of infection with COVID-19 in industrial settings.