The aim of this study was to investigate the one-year development of self-reported sleep problems in workers with no sleep problem at baseline, and to evaluate the role of work stress in the etiology of a new episode. A prospective design was employed. A total of 816 employees with no sleeping problems during the past three months completed a baseline questionnaire concerning their general health, working hours and working conditions. One year later they were contacted again to ascertain whether they were experiencing problems sleeping. At the follow-up, the three-month point prevalence of self-reported sleep problems for this population was 14.3%. While controlling for age and gender, it was found that irregular working hours and general health were not significantly related to the development of a new episode of sleeping problems. However, stress in the form of a 'poor' psychosocial work environment increased the risk of a new episode by more than twofold (odds ratio 2:15). The attributable fraction suggested that eliminating stress could prevent 53% of the cases. In a population of employees with no reported sleeping problems, 14.3% developed a sleeping problem during the coming year. Even when controlling for possible confounders, stress in the form of a 'poor' psychosocial work environment doubled the risk of developing a sleep problem.