Problems of persons with disabilities should be examined also at a legal angle. Creation of legal instruments of support for such persons is absolutely crucial. With the assumption that tax law is one of the more intrusive branches of law, which on the other hand may serve non-fiscal, including social goals, this study analyses those instruments which may be elements of such support. The author concentrates on regulations of the personal income tax and the rehabilitation relief regulated by them as a tax credit that is fundamental for this research area. Special focus is given to interpretation dilemmas that accompany the application of these regulations, which may greatly limit their efficiency. The analysis of the normative material and views of legal scholars and commentators and the judicature has allowed a number of conclusions, de lege lata and de lege ferenda alike.