Aims.To determine the impact of HLA compatibility measured by the Compatibility Index, on survival, rate of rejections, malignancies and infections in patients after heart transplantation (HTx). Methods. We carried out a retrospective analysis of 182 consecutive patients who underwent heart transplantation in our center from January 2001 to April 2010. According to degree of HLA-A, B and DR matching (Compatibility Index, CI) the patients were divided in two groups, Group A (n=83) with an IC 0-17 and group B (n=99) with an IC 18-26. There was no significant difference in demographic parameters between recipients and donors. Results. We found no difference in rates of rejections or infections between Group A and Group B (AR: 22 (26.5%) vs. 34 (34.3%), P=0.2539; infections: 21 (25.3%) vs. 27 (27%) P=0.7637). The distribution of infections in terms of type (bacterial, viral, fungal, including Aspergillus) was similar in both groups. The incidence of malignant tumours was infrequent (3 (3.6%) vs. 4 (4.0%), P=0.8817). We found trend toward lower level of tacrolimus in Group A. Long term survival was similar in both groups. Conclusions. Based on the results of our single-center trial, we found no impact of higher degree of HLA-A,-B, and -DR matching on survival, rejection episodes or infection. Further large studies are necessary to confirm our hypothesis that subjects with better HLA compatibility could require lower dose immunosuppression.