Objective. To evaluate employment, career problems and job-related handicaps in adults with complex or mild congenital heart disease (CHD). Design. Cross-sectional. Method. Data were obtained from 76 patients with complex and 80 with mild CHD who were known to the Department of Paediatric Cardiology at the Leiden University Medical Center, the Netherlands. They were selected on the basis of diagnosis and year of birth (1968-1982). They completed a self-report questionnaire on education, employment and handicaps. A total of 224 patients were approached; the response from the groups was 88% and 58% respectively. Results. Participants included 83 women and 73 men. Their average age was 24.5 years (parameters: 17-32). In the study groups, 45 of 76 patients with complex CHD (59%), and 61 of 80 patients with mild CHD (76%) (p = 0.002) had paid work. Patients aged 25-29 years with complex disease had a statistically significantly lower rate of employment (64%) than the same age group in the general population (83%). Complex CHD and a lower level of education increased the risk of unemployment (odds ratios 4.8 (99% CI: 1.2-19.6) and 4.7 (99% CI: 1.3-17.2), respectively). Of the patients with complex CHD, 55% (42/76) experienced disease-related career problems, in contrast to 1% (1/80) of the patients with mild disease. Both CHD groups showed more job-related handicaps in the area of mobility than the reference group in the general population (p = 0.002). In the mild CHD group, this could be attributed to other, non-cardiac diseases. Conclusion. Patients with complex CHD had a lower level of job participation, on comparison with patients with mild CHD and their peers in the general population. Many experienced career problems or mobility problems at work. These problems may be prevented or limited by career counselling focussing on physical abilities and level of education.