A survey of employment problems in a random sample of diabetic patients and a group of control subjects aged 17-65 years was carried out in eight centres in the UK. Data were linked to information collected from patients' diabetic clinic notes relating to the presence and treatment of any diabetic complications and quality of diabetic control. Difficulties in obtaining employment because of diabetes were reported by 13% of diabetic patients, and because of illness by 2% of control subjects (p less than 0.001). Nine percent of diabetic patients and 2% of control subjects reported having to change their job because of their illness (p less than 0.001), and 7% of people with diabetes and 2% of people without diabetes reported losing a job because of their illness (p less than 0.001). Diabetic shift workers were twice as likely as control subjects working shifts to experience problems with their job (18 vs 8%, p = 0.045). Reports of any sickness absence in the last 12 months were not significantly different for people with and without diabetes (49 vs 45%). Sickness absence in excess of 20 days in the last 12 months was more common among diabetic patients than control subjects (29 vs 16%, p less than 0.001). People with diabetes are more likely to experience problems in obtaining employment and staying employed than people without diabetes.