Today, international investments have increased using Islamic commercial contracts. These contracts can be divided into five areas, including 1. Contracts based on purchase and sale, 2. Contracts based on partnership, 3. Contracts based on lease, 4. Contracts based on payment, and 5. Other contracts. The thing is that these contracts have brought Islam into the field of international investment law. Purpose: the main purpose of the article is to answer this question, how have Islamic commercial contracts brought Islam into international investment law? Research Methods: In this study, quantitative and qualitative methods have been used to examine how Islamic commercial contracts play role in investment process. Conclusion: In response to the main question, the current article has concluded that Islamic commercial contracts, given their nature, bring Islam into international investment law in three steps: first, in the direction of concluding a contract, second, in line with the using the opinions of international Islamic councils, and third, in connection with the arising international investment disputes