question: Objective: This study examined the relationship between support for workers with illness and work functioning impairment during the COVID-19 pandemic. Methods: An internet survey was conducted on December, 2020. We included 22,388 subjects for analysis. A question was used to determine whether subjects need support from their company to continue working in their current health condition. The odds ratios (ORs) of relation between work functioning impairment and necessary of support for sick workers were estimated using multilevel logistic regression analysis. Results: The OR of work functioning impairment among sick workers not receiving support was 5.61 (95% confidence interval (CI) 5.19-6.06, p<0.001) and those receiving support was 1.82 (95% CI 1.64-2.03, p<0.001) compared to healthy workers. Conclusions: This study suggests that providing support to workers with illness may improve their work functioning impairment.