This thesis addresses the fiduciary, a legal institute which originated in Roman law and is in its basic features, with some modern adjustments, still present, in particular in transition countries. The purpose of the institute, securitization of a claim by transfer of the property ownership or property rights where the debtor – fiduciary debtor, or a third person, transfers to the creditor – fiduciary creditor, the property of things or rights in order to secure the creditor’s claim. After the claim has been received or is terminated in another way, except in case the fiduciary creditor has acquired full property right or right, the fiduciary creditor has the obligation to retransfer the property or other right that had been transferred to him. The fiduciary was introduced in the Croatian legal system with the 1996 Seizure Act and the 1996 Property and Other Proprietary Rights Act, offering two possibilities to establish a fiduciary relationship, while there is a third possibility arising from legal contract regulations. This paper has explained the purpose and the historical development of the institute as well as its positive legal system and the possibilities of its implementation in the Republic of Croatia.