In the world business development, Letter of Credit is known as the international payment system. To increase knowledge as an economist or a user of the Letter of Credit, it is necessary to research about the effects of the used of the Letter of Credit towards cash flow. The objectives of this research are to know the process of Letter of Credit transaction and the impact of using Letter of Credit as an import payment towards cash flow of PT. Pindo Deli Pulp and Paper Mills. From the research results can be proved that the used of Letters of Credit in PT. Pindo Deli Pulp and Paper Mills is helping companies to simplify the payment process, and the used of Letters of Credit affect the company's cash flow.