The author raises the issue of the legal consequences of a declaration of intent made in error in labour relations. She considers the existence of a legal loophole in labour law to justify reference to the provisions of civil law and various proposals for the proper application of Art. 84–88 of the Civil Code, ranging from exclusion applicability of the provisions of civil law on the defects of the declaration of intent to labour relations, the admission of the application of those provisions with the various modifications, or the application of the provisions of the deficiencies of the declaration of intent directly, so without making any changes. The author also considers the legal consequences of the application of Art. 84–88 of the Civil Code to labour relations, in particular, on the one hand, the effects of the cancellation of legal action ex tunc in the situation where the work was already done on the basis of an annulled contract and, on the other hand, if the contract was annulled before the employee started work. She also presents the legal structure of the error in declarations of intent and discusses the most frequent causes of errors in declarations of intent in labour relations.