The aim of the paper is to analyse the Hungarian family law rules regarding parental agreements on children’s parental custody, contact and child maintenance, including their high legal and judicial requirements and strict standards. Parents are regularly supported to agree on issues concerning their children in cases when they no longer live together, as this corresponds to the principle of autonomy. However, they must enter into agreements that meet the requirements of the child’s best interests regardless of whether they lived in marriage or de facto cohabitation. The agreements must serve the interests of the partners and those of the child but not only at the time of concluding the agreement but also later. The question emerges of how either partner may request the agreement to be modified if the parents cannot agree new terms. Several aspects of the regulation, such as the judiciary, need to be considered and envisaged to evaluate the legal environment of parental agreements. This investigation is validated by the fact that it is not only the parents’ but also the state’s task to support the conclusion of agreements that protect the parties and their child’s interests and, if necessary, make the amendment of agreements possible.