BackgroundThe number of industrially injured workers (IIW) is increasing in Korea. However, little research has been conducted on whether first aid is performed at industrial sites or on the association between first aid for industrial injuries and the prognosis of IIW, including healthcare utilization.MethodsA total of 3,092 participants (2,562 males and 530 females) were analyzed during the 4-year study period, which contributed to 11,167 observations. Healthcare utilization was evaluated based on the number of outpatient visits, hospitalizations, and duration of hospitalization using a generalized estimating equation Poisson regression. Several time-varying socioeconomic characteristics and information about the injury were adjusted, and transfer time to the medical institutions was also considered.ResultsDuring 4-year after the termination of medical treatment, participants who had not receive first aid visited outpatient clinics 15.243 times per year, and those who had visited 13.928 times per year, which is 16.16% less (adjusted relative risk [aRR]: 0.838, 95% CI = 0.740–0.950). Participants who had received on-site first aid with less than a 0.5-hour transfer time to the medical institutions visited outpatient clinics 14.87% less per year than those who had not received first aid (aRR: 0.851, 95% CI = 0.750–0.966).ConclusionTo reduce the long-term outpatient utilization rate for IIW after medical treatment, on-site first aid must be provided in a timely manner. Employee education and first aid training are also necessary.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12995-023-00380-8.