Determination of legal rulings in Islam on food that has been modified DNA is very difficult. This is because the Muslim jurists themselves have different opinions in their legal decisions to determine the foods that have been modified DNA by modern processes or well-known as istihalah in Islamic legal system. Therefore, it seems that the Muslim contemporary jurists always do an effort to solve the problem of food based on evidence taken from the Quran and the Traditions of the Prophet. Thus, the objective of this study is to identify the istihalah process that is of a major importance factor in transforming DNA of food, changing the unclean substance to the new products that benefit consumers. In addition, this study also seeks to examine all views of Muslim jurists in determining the legal ruling of istihalah. In addition, the study also provides a mechanism for the determination of the legal ruling in Islamic law, especially in the case of istihalah that produces a good product for publics. This study uses qualitative methods through instruments of data collection and content analysis based on comparative method. The findings of this study indicate that all products will be evaluated based on the final products. If the final product does not have any unclean substance, the law permits to consume it. Otherwise, it is unlawful.