Analysis of Roman sea loan from the modern perspective of Project Finance has been now conducted in the relation to the methods of gaining profi t. In pecunia traiecticia interest where considered not as a remuneration for usage of creditors money but as the price for taking over the risk by the creditor. Thus the Latin phrase periculi pretium (D. 22,2,5) has become so famous. The unique character of the interest caused the evolution of the legal construction of the sea loan. At fi rst it was necessary to agree on the fenus nauticum in the stipulation added to the loan. Then, jurisprudence confi rmed the possibility of suing debtor for interest also on the ground of the mere pactum. Another aspect of the sea loan which implies the similarity with Project Finance was the privileged position of interest which were not constrained by the legal limits of interest as in the case of typical mutuum. Strict connection between the contract of sea loan and the risky venture one can easily notice when taking into consideration that the agents of creditor were participating in that venture together with the debtor. Moreover, the creditor received not only the loan and the interest but also a remuneration for time which his slaves spent with the debtor. The additional stipulation for agents participation and the character of liability of debtor’s heirs provide a new perspective of the sea loan as a mean to fi nance risky ventures in antiquity. Modern Project Finance resembles to high extent the ancient solution and that enables further studies on the topic.