Many workers with one Workers’ Compensation Board (WCB) claim make further claims. If the characteristics of the job, initial injury or worker were predictive of an early second claim, interventions at the time of return to work after the first claim might be effective in reducing the burden of work-related injury. This report explores the characteristic of those who make a second claim. Records of all Alberta WCB claims from January 1, 1995, to December 31, 2004, for individuals 18 to <66 years old were reviewed. For each individual’s first claim, sex and age of claimant, type of injury, type of accident, occupation, industry, an indicator of company size, and industry claim rate were extracted, as well as the date of any second claim. The likelihood of second claim and mean time to second claim were estimated. Multivariate analyses were performed using Cox regression. 1,047,828 claims were identified from 490,230 individuals. Of these, 49.2% had at least two claims. In the multivariate model a reduced time to second claim was associated with male sex, younger age and some types of injury and accident. Machining trades were at highest risk of early second claim (hazard ratio [HR] 2.54 compared with administration), and of the industry sectors manufacturing was at highest risk (HR 1.37 compared with business, personal and professional services). Some caution is needed in interpreting these data as they may be affected by under-reporting and job changes between claims. Nonetheless, they suggest that there remains room for interventions to reduce the considerable differences in risk of a second claim among workers, jobs and industries.