The aim of the study was to evaluate health-related quality of life (HRQoL) of Hungarian children attending a pediatric cardiology outpatient unit with the Pediatric Quality of Life Inventory (PedsQL) questionnaire. The PedsQL Generic Core Scales and Cardiac Module were administered to 254 families including 195 children during a pediatric cardiology outpatient visit, and 525 families including 373 children from the general population were examined by the PedsQL Generic Core Scale by a postal survey. The relationships between PedsQL scores and patient characteristics were analyzed. Hungarian children attending a cardiology outpatient unit as an entire group and patients with severe heart diseases report significantly lower physical functioning than the general population, while more HRQoL dimensions are negatively affected according to the parents' opinion. Children with congenital heart disease of mild and great complexity also report impaired psychosocial functioning. HRQoL impairment is concentrated to the age of 5-7 years. Comparing our results with previous ones on U.S. pediatric cardiologic samples, we found significantly lower scores mainly for the physical functioning and heart symptoms subscales. This HRQoL study with an internationally well-validated instrument on children with heart disease in a Central European country highlights certain aspects of the health-care system and brings the possibility for the assessment of pediatric cardiology outcomes in a more comprehensive way.