The contribution is devoted to the approximation of the principle of subsidiarity of criminal repression in relation to the crime of defamation, through the lens of the Constitutional Court of the Czech Republic. I decided to work on the mentioned topic with regard to the current decision-making practice of the Constitutional Court, which concludes that the criminal penalty of defamation should be reserved for the most serious interference with personal rights, and from this point of view it is necessary to assess whether the formal features of this crime have been met.