Labour relations are contractual relations. In this matter, labour relation has primacy over another contract, hence, if an employer signs a contract with a worker for performing work which with regard to the nature and type of work and the powers of an employer has the features of work for which labour relation is established, it is considered that the employer has concluded labour relation with the worker, unless the employer proves the contrary. Performing the programme of supplementary activity is beyond any doubt very important and significant. By doing so, higher health institutions gain additional revenues which are important for their activity and development. Probably the most important amendment to the Labour Act contained in the Act on Amendments to the Labour Act, with probably the most effects, is the amendment to the Article 10 of Act which regulates employment contract on a fixed-term basis. The amendment to the Act allowed for the first employment contract to be concluded on unlimited fixed-term basic (for the period of two, five, ten years, etc.), however, if it has been concluded on a period longer than three years, the fixed-term employment contract may not be concluded again. If the first contract has been concluded for a period shorter than three years, a subsequent contract has to contain an objective reason. Nevertheless, a serious doubt remains as to whether the first fixed-term employment contract needs to contain an objective reason for its conclusion on the fixed-term basis.