To study the effects of an intervention based on social marketing to persuade workers to use personal protective equipment (PPE) in constructing subway stations in Isfahan, Iran. This was a quasi-experimental study. Two stations were selected as intervention and control groups. Intervention was designed based on results of a formative research. A free package containing a safety helmet with a tailored message affixed to it, mask and gloves and an educational pamphlet was delivered to the intervention group. After 6 weeks, behaviours in the intervention and control stations were measured using an observational checklist. After the intervention, the percentage of workers who used PPE at the intervention station increased significantly. OR for helmet and mask usage was 7.009 and 2.235, respectively, in the intervention group. Social marketing can be used to persuade workers to use PPE in the workplace.