Objectives Approximately 5–10% of US jobholders report working multiple jobs within the same week, and up to 20% have reported working in more than one job within a year. However, occupational injury surveillance research has largely explored only exposures at the primary job or the job in which the injury occurred. The objective of this study was to compare the risk of injury for those working in multiple jobs (MJH) with those working in only one job (SJH).

Methods The National Health Interview Survey is the only national survey to collect information annually about self-reported injuries in the last 3 months information about working multiple jobs. Using information for years 1997–2011, we calculated the rate of multiple job holding in the US and compared characteristics and risk of injury (work and non-work) with those who worked in only one job.

Results The risk of work and non-work injury was higher for MJHs compared with SJHs (9.9 vs. 7.4 non-work injuries per 100 workers, and 4.2 vs. 3.3 work injuries per 100 workers) and the rate of injury remained higher after controlling for work hours (p < 1). There was a significant elevated risk of injury for some subgroups (e.g. young workers aged 18–24 who worked in multiple jobs had a risk of injury, both during outside of work, of 19 per 100 workers, almost 40% higher than their SJH counterparts).

Conclusions Our findings suggest that multiple job holding is associated with an increased risk of injuries (work and non-work) and must be considered in injury surveillance. Suggested pathways exist for MJH to increase the risk of injury: fatigue, inexperience in jobs, hurried behaviour, or additional biological/emotional stress from alternating between different types of exposure.