Little population-based, prospective research has been conducted to examine the demographic and work-related determinants of occupational injury or illness. This study examined the relative contribution of sociodemographic characteristics and work factors to the likelihood of a work-related disability or illness. In a representative sample of adult Canadians 25-70 years old from a prospective survey, a hazard modelling approach of time to work disability absence from the start of a new job was estimated with the following predictors: age, gender, type of job (manual, non-manual, and mixed), hours worked, highest education achieved, multiple concurrent job, job tenure, school activity, union membership and living in a rural or urban area. Workers holding manual or mixed jobs and having a low education level were factors independently associated with the increased likelihood of a work disability absence. Gender was not independently associated with work disability absences. A strong job tenure gradient in the unadjusted work disability absence rates was virtually eliminated when controlling for demographic/individual and other work factors. In multivariate analyses, work-related factors remained predictors of work disability absence whereas individual characteristics such as gender did not. The exception was workers with less education who appeared to be particularly vulnerable, even after controlling of physical demands on the job. This may be due to inadequate job training or increased hazard exposure even in the same broad job category.