The influence of specific tax knowledge on attitudes towards taxation was examined. The study reports significant changes in attitude to one's own tax evasion and attitude to fairness of the tax system. Following increases in tax knowledge, respondents consider their own tax evasion as more serious, the perceived fairness in taxation increased, and attitudes towards other people's tax evasion became stricter. In agreement with previous research, these tax attitudes have an influence on reforced inclinations towards tax evasion and tax compliance.