UNLABELLED: Nowadays, due to the development of cardiac surgery, pediatric cardiology and anesthesia, almost every congenital heart disease can be corrected totally or partially. The increasing number of surgical corrections will lead to better life quality. The surgical mortality has decreased significantly, even in the most complex cases. Only few cases can not be treated surgically. The aim of this study was to examine these positive changes, what they mean in the treatment of premature babies with congenital heart disease. These patients are endangered because of their age as well, they require special treatment and the surgical treatment has always meant high risk, urgent interventions. PATIENTS: between 01. 01. 1975. and 31. 12. 2003. 447 premature babies were operated on. The patients were divided into 3 subgroups by their weight: I: 470-1500 gr. - 19 patients, II: 1500-2000 gr. - 93 pts., IIl: > 2000 gr. - 335 pts. There were 69 corrective surgical procedures performed mainly after 1998. RESULTS: Overall early mortality: 81 patients (18.1%). Detailed mortality: group I.: 0%, group 11: 23 (24.7%), group III.: 58 (17.3%). The early mortality reduced from 21.6% to 6.3% (closed procedure), and 27.7% to 10.8% (ECC operation). The successful operations in the smallest weight groups were as follows: On ECC: Total Anomalous Pulmonary Venous Return (1600 g), Transposition of the Great Arteries--Arterial Switch (1800 g), Ventricular Septal Defect (1800 g), Aortopulmonary fenestration (2000 g), Hypoplastic Left Heart Syndrome-Norwood procedure (2200), AV septal defect (2300 g), Interrupted aortic arch + Ventricular Septal Defect (2300 g), Truncus arteriosus (2500 g). Without ECC: Coarctation of the aorta (930 g), Patent Ductus Arteriosus (470 g). CONCLUSION: Nowadays the possibilities and the chances of the corrective procedures of congenital heart diseases in those patients with bodyweight of over 2000 g and in those that are mature babies are the same. In those patients with bodyweight 1500-2000 g procedures without ECC had good results, on-pump procedures had higher mortality rate, but the long-term results were acceptable. At the moment only procedures without ECC are performed on babies with weight under 1500 g--but with higher risk. Our effort is to perform ECC operations in patients with bodyweight less than 1500 g.