Every acquisition of rights to prestations (benefit payments) from the Alimony Fund is always preceded with a realization of duty of alimony (art. 4 of the Alimony Fund Act of July 18, 1974). The notion of duty of alimony does not have a precise meaning. The author attempts at reconstructing a meaning of that notion. It is found in the conclusion that adll legal bonds conséquent upon familly law regulation, connecting the person entitled with the person obliged, are the grounds for appearance of duties of alimony. On the base of the adopted criterion all duties of providing the means of maintenance and possibly means of education established according to the regulation of art. 753 of Gode of Civil Procedure and Family and Guardians...