This paper deals with the institute of marital agreement in the Croatian family law. Marital agreement represents a crucial element in regulating property relations in marriage, as well as in same sex and extramarital relationships. Briefly presented are the property-law relations of spouses in Roman law and the General Civil Code. The principles of family law apply to marriage agreements and general characteristics of marriage agreements are explored, which would not be possible without a brief presentation of the norms of general civil law as lex generalis due to the very small number of the Family Act provisions regulating marital agreements. Its purpose, the question of its validity, and its effect on third parties have been considered. The question arises about the need for the introduction of a register of marital agreements in the Republic of Croatia, along with the identified advantages of its establishment, and suggestions regarding the potential effects among spouses and third parties. Despite the relatively small number of court cases at the start of regulating this institution, court decisions that have a significant impact on understanding and interpreting marital agreements are analyzed. The object of the marital agreement is not explicitly determined by the Family Act, in connection with which emphasis is placed on contracting foreign law as applicable and the question of maintenance as an exceptions from the autonomy of contracting. In conclusion, reasons for and against introducing marital agreements are presented, offering a comprehensive review of the arguments put forward.