AbstractBackgroundEvidence regarding the unequal burden of occupational injuries between workers employed by temporary agencies and those in standard employment arrangements is unclear. Studies range from no significant differences in risk to substantial increased risk for temporary workers. The purpose of this study is to compare the workers' compensation experience of a large cohort of temporary agency employed workers with those in standard forms of employment.MethodsWashington State Fund workers' compensation data were obtained for claims with injury dates from January 1, 2003 to June 30, 2006, resulting in 342,540 accepted claims. General descriptive statistics, injury rates (per 10,000 FTE), and rate ratios (temp agency/standard employer) were computed by injury type and industry.ResultsTemporary agency employed workers had higher rates of injury for all injury types, and higher median time loss (40 vs. 27 days) but lower time loss costs (median $1,224 vs. $1,914, P < 0.001) and lower medical costs ($3,026 vs. $4,087, P < 0.001) than standard arrangement workers. Temporary agency workers had substantially higher rates for “caught in” and “struck by” injuries in the construction (IRR 4.93; 95% CI 2.80–8.08) and manufacturing (IRR 4.05; 95% CI 3.25, 5.00) industry sectors.ConclusionTemporary agency employed workers have higher claims incidence rates than those in standard employment arrangements. The rate ratios are twofold higher in the construction and manufacturing industry sectors. More research is needed to explore potential reasons for this disparity in occupational injuries. Industry or some measure of job exposure should be included when comparing injury rates in different types of employment in order to better identify areas for prevention. Am. J. Ind. Med. 53:135–145 2010. © 2009 Wiley‐Liss, Inc.