Objective: By employing the widely used and accepted methodologies of case-mix complexity adjustment in congenital cardiac surgery, we tried to evaluate our performance and use the ABC scores for a case complexity selection that may have different outcomes in various centres. Methods: We analysed outcomes of cardiac surgical procedures – with or without cardiopulmonary bypass – performed in our institution between January, 2008 and December, 2011. Data were collected from the European Association for Cardio-Thoracic Surgery database. Together with prospective collection of these data, the data of all patients sent abroad to foreign cardiosurgical centres were recorded. Results: During the period of study, 634 operations were performed; among them, 60% were performed in Croatia and 40% in foreign cardiosurgical centres. The number of operations performed in Croatia showed a linear increase: 55, 78, 121, and 126 operations performed in the years 2008, 2009, 2010, and 2011, respectively. Early mortality rates were 1.82%, 5.41%, 3.64%, and 3.48% in 2008, 2009, 2010, and 2011, respectively. The increase in the number of operations was followed by a satisfactory low average mortality rate of 3.85%. The mean ABC score complexity for operations performed in Croatia was 5.77. We determined a linear correlation between ABC score and early mortality, especially for the more complex operations. Conclusion: The use of standardised risk scores allows selection of complex cardiac diseases, which may have very different outcomes in various centres. In our case, those with higher ABC scores were correctly identified and referred for treatment abroad. In this way, we allowed gradual progress of the cardiosurgical model in Croatia and maintained an enviably low mortality rate.