This article deals with the issue of administrative decision, which represents one of the principal forms of the realization of public administration in the Czech Republic. Even if the Czech legislation provides for its issuance a number of requirements in relation to its content and form, in practice, however, there are violations of these legal conditions and requirements and then we talk about a defective administrative decision. According to how to remedy the defective administrative acts, distinction is made between formally defective administrative decisions, factually inaccurate decisions, unlawful decisions, and next to them, separately null administrative decisions. The main attention is paid to the nullity, because only the nullity represents the most serious and also irremovable defect of an administrative decision. As the null decision does not exist from the perspective of law, it is not able to affect the rights and duties of its recipients. The null acts, as the only category of defective administrative acts, constitute an exception to the principle of the presumption of validity and correctness of administrative acts.
