Introduction Data are lacking on under-reporting of occupational injuries (OI) among precariously employed workers in Sweden, challenging effective surveillance of OI and targeted preventive measures.

Objective To estimate the magnitude of under-reporting of OI among precarious and non-precarious workers in Sweden in 2013.

Methods Capture–recapture methods were applied using the national OI register and records from a labour market insurance company. All employed workers 18–65 resident in Sweden in 2013 were included in the study. Injuries were linked using personal identification numbers. Employment data were obtained from the national labour market register to construct precarious employment level, while injury severity (no healthcare/only outpatient/hospitalised) was constructed with data from the National Patient Register. Under-reporting estimates were computed stratifying by OI severity and by socio-demographic factors, occupation and precarious employment level.

Results Overall, under-reporting of OI was consistently higher across all socio-demographic factors for the very precarious group (very PER), followed by the precarious group (PER) and lastly the standard employment relationship group (SER). Under-reporting was higher among females compared to males (17.8%, 95% confidence interval (CI) 17.4–18.3), and younger compared to older workers (19.8%, 95% CI 18.6–21). Notably under-reporting increased with educational level across all employment groups (20.9%, 95% CI 20.0–21.9). Under-reporting of the OI decreased as injury severity increased and was higher with highest level of precariousness in all groups of severity.

Conclusions This is the first register-based study in Sweden to empirically demonstrate that under-reporting of OI is higher among precariously employed workers. OI under-reporting may represent unrecognized injuries that especially burden precariously employed workers´ financial, health and social outcomes, shifting consequences from the employer to the employee.