Objectives: To evaluate difficulties in daily life, and satisfaction with level of knowledge about their disease, in patients with congenital cardiac disease in order to improve counselling. Methods: A self-administered questionnaire was completed by 80 patients with mild, and 76 with complex, congenital cardiac disease. They were aged from 17 to 32 years. Results: Even patients with only mild malformations experienced difficulties related to their disease, but being found in only 11%, these were significantly less than those uncovered in 87% of those with complex disease (p < 0.001). Those patients with complex malformations frequently felt restricted in choices because of their disease in areas such as sport (59%), employment (51%), and education (34%). Other difficulties reported were: paying a higher premium for life insurance (29%), having to give up on a sport (28%), and being excluded from a job (18%). Depending on the item, between one-fifth and two-thirds of participants reported gaps in knowledge, most frequently for “causes of congenital cardiac disease”, “future consequences”, and “family planning”. For 53% of those with mild anomalies, and 93% of severely affected patients, the cardiologist is the most important source of information. Conclusions: A minority of adults with mild, and a majority of those with complex congenital cardiac disease report difficulties in daily life. A substantial number of these patients feel that they have an inadequate level of knowledge about their disease. Our results suggest the need for a specific programme of counselling.