Resumen del autor, extraído del trabajo. In the first part of the article, it is tried to define the non-risky methods of funding for oil and gas upstream industry. And then, various methods of foreign funding for the I.R. of Iran’s oil and gas upstream are examined. In this respect, in addition to the review of Iran’s Oil Buy-back formula, supplementary related information is mentioned. At the end, feasibility of using other sources of foreign funding for Iran’s oil and gas upstream projects are assessed. The topics of the paper are as follows: 1. Introduction 2. Analysis of the Process of Funding of the Upstream Sector 3. Strategies in Funding Large Projects in the Oil Upstream Sector 4. I.R. Iran; the Trend of Investment in its Oil and Gas Sectors 5. The Principals Governing Buy-back Contracts in Iran 6. Oil Buy-back contracts in the 2nd Development program 7. Finalized Upstream Buy-back Contracts 8. The Outlook for Oil Buy-back Contracts 9. An Analytical View of Other Methods of Funding 10. Conclusion 11. References