OBJECTIVES: The aim of the present study was to predict the risk ratio of sickness absence lasting ≥2 weeks due to shift work among Danish workers caring for the elderly during the evening and at night. Methods A sample of Danish carers of the elderly were interviewed in 2005. The response rate was 78%. A cohort of 5627 shift and day workers was followed for sickness absence lasting ≥2 weeks and for sickness absence lasting ≥8 weeks in a sickness compensation register covering all social transfer payments in Denmark. Results Among the evening workers, the rate ratio (RR) of sickness absence lasting ≥2 weeks was 1.29 (95% confidence interval (95% CI) 1.10–1.52). The rate ratio for sickness absence lasting ≥8 weeks was 1.24 (95% CI 0.99–1.56). Conclusions Evening work may cause long-term sickness absence lasting ≥2 weeks.