The thesis deals with singular succession in Roman inheritance law. The concept and topic of inheritance law will be briefly explained in the introduction. Furthermore, in connection with the well-known fact that a large number of rules and institutes of a number of contemporary legal systems rest precisely on Roman foundations, the paper points to the presence of certain forms of Roman singular succession mortis causa in the contemporary Croatian law, without developing a deeper analysis. Aiming at elaborating the topics of the paper in as much detail as possible, an accompanying chapter provides a comparative legal presentation of universal and singular succession in Roman inheritance law. The main part of the paper analyses the forms of singular succession mortis causa exclusively within the Roman legal framework. The chapters deal with legacy, fideicommissum and donation in prospect of death. The paper presents, among other things, the features and development of the three institutes, as well as their differences and common elements. In line with the above facts, these institutes occupy the final Roman legal position in the Justinian law.