Occupational falls are a significant concern among older workers. Although recent cross-sectional studies have indicated a potential association between frailty and occupational falls among older workers, the causal relationship remains unclear. This longitudinal study aimed to investigate whether frailty is a risk factor for occupational falls among older workers using a longitudinal design. This was an Internet-based prospective cohort study. A total of 5,000 older workers (aged 60-75 years) were recruited, with 2,873 participants meeting the inclusion criteria for the follow-up survey. Frailty was assessed using a frailty screening index based on the Fried phenotype model. Occupational falls were defined as those that occurred during the follow-up period. Among the participants, 13.9% were frail. The incidence of occupational falls was higher in the frailty group (11.6%) than that in the non-frailty group (4.9%). In the multivariate-adjusted model, frailty was significantly associated with occupational falls (relative risk: 2.10, 95% confidential interval: 1.51-2.94). Frailty is a significant risk factor for occupational falls among older workers. Employers should consider implementing health-management strategies that focus on frailty to prevent occupational falls in this population.