Testamentary freedom is one of the basic pillars of inheritance law in any legal system. In Eurocontinental law, it is limited, inter alia, by the right of the heir to a statutory portion (forced heirship). On the other hand, Anglo-Saxon law does not recognize the forced heirship. In Europe, there is a tendency to narrow the circle of mandatory heirs. Testamentary freedom is guaranteed in modern Constitutions, while, on the other hand, it is disputed whether the right to inheritance, guaranteed by the Constitutions, also includes the right of heirs to a mandatory portion. In German law, which is based on the decision of the Federal Constitutional Court from 2005 the right to a forced heirship is considered as a part of public order, even as a part of international public order. On the contrary, in France and Hungary, in situations of crossborder inheritance, the right to a forced heirship does not belong to the domain of international public order. Considering the language and aim of Articles 58, 59 and 66 of the Constitution of the Republic of Serbia, it is difficult to argue that the heir’s right to a mandatory share is covered by the constitutional guarantees enshrined in Articles 59 and 66. On the contrary, Article 58, which guarantees peaceful enjoyment of property rights, and Article 23 (2), guarantee freedom of testamentary disposition. The same is the case with the European Convention on Human Rights, which guarantees freedom of testamentary disposition, but not the right to inherit. A foreign law that does not recognize the right to a forced heirship is not contrary to domestic public order. It is possible that the foreign law contains some kind of functional equivalent that aims to financially secure the mandatory heirs which is the case in Anglo-Saxon legal systems. The application of the lex fori fori allong with the application of the lex successionis is contrary to the principle of fairness in Private International Law. Also, it results in dépécage which is undesirable in PIL and runs counter to the principle of the unity of inheritance property. The application of foreign law governing the inheritance in the Serbian PIL could be limited only in exceptional cases. For example, when the foreign applicable law does not recognize any functional equivalent to a mandatory portion or when the foreign applicable law does not recognize the decedent’s minor children any claim to the inheritance property, so that they remain deprived of means necessary for life and, therefore, fall under the burden of state social assistance. Also, for the application of the part of lex fori, it would be necessary that the case of crossborder inheritance is closely related to domestic legal order. For example, that the mandatory heirs are citizens of Serbia with domicile in Serbia.