Newly diagnosed mild Type 2 diabetic patients, aged 30-55 years, were included in the prospective, multi-centre Diabetes Intervention Study. They were randomly allotted to either an intervention group receiving intensified health education or to a control group on usual care. This paper reports the incidence, duration of and causes for absence from work due to any disease in the patients who were working during the first 5-year follow-up. Data from 817 patients could be taken into account. 14.5% of the intervention patients and 17.3% of the control patients had never been on the sick list. Those patients who had undergone intensified health education were listed sick less often. Women showed a higher work absenteeism in either group; they had higher blood pressure and higher body mass index at entry. Cardiovascular diseases and musculo-skeletal disorders were major reasons for absence from work. However, when compared to the general population, these Type 2-diabetic patients were approximately four times more often on the sick list. Thus, the health education programme of the Diabetes Intervention Study was shown to be effective with respect to work absenteeism. Teaching patients is recommended as an important part of the therapeutic regimen.