BACKGROUND There is some evidence that mental ill-health (MIH) is associated with injury at work, but data are sparse. OBJECTIVE To examine, within a cohort of workers with a first workers' compensation claim, whether those with a history of MIH had a higher than expected number of second claims. METHODS All Workers' Compensation Board (WCB) records from January 1995 to December 2004 were linked to administrative health records, and a physician diagnosis of MIH in the 48 months prior to the first WCB claim extracted. The first and second (if any) claim for each worker were identified and time to second claim calculated. Survival time to second claim was estimated by Cox regression with history of MIH as a covariate. RESULTS Results were available for 389 903 WCB first claimants. Of these 53% of men and 38% of women had a second claim, with a mean time between claims of 768 days (men) and 785 days (women). Those with a history of MIH were somewhat more likely to make a second claim and, in the survival analysis, to make this claim sooner. Type of injury at first claim did not appear to modify this effect. CONCLUSIONS Workers with a recent history of MIH at the time of making a first WCB claim for a work injury are at greater risk of a second injury, leading to a new claim. Strategies to get workers back to work after the first injury/claim should include management of MIH to reduce the risk of further injury.