This study investigates the determinants within socio-demography, health behaviour, employer characteristics, and psychosocial and physical work environment for return to work. In 2000, a total of 5357 employees were interviewed regarding age, gender, family status, education, health behaviour, employer characteristics and work environment. They were followed in a national register for 18 months in order to identify subjects with 2 weeks or more of sickness absence. They were followed for an additional 12 months in order to establish associations between baseline measurements and time to first return to work. A total of 930 (17.4%) employees experienced sickness absence in the 18 months after baseline. During the 12-month follow-up, 856 (92.0%) returned to work, the mean absence period being 6.6 weeks. Prolonged time to first return to work was associated with female gender, increased age, no post-school education, being employed by a public employer, working at a workplace with 20 or more employees, high emotional demands in work, high job insecurity and sedentary work. There were no associations between health behaviour variables and return to work. The study indicates a potential for promoting return to work through interventions targeting emotional job demands, job insecurity and decreasing the risks associated with sedentary work.