Mimar Sinan; who constructed his buildings by combining his architecture skills, engineering, and craftsmanship in the Ottoman Empire's socialy, economicly and politicaly matured period; known as one of the famous representatives in the architectural field of Ottoman culture. Many national and international research has been made dealing with this period of Ottoman architecture and Mimar Sinan. However, there is a limited number of analitical resources about Mimar Sinan's buildings. With this study, which has not been previously studied in detail and was over identified with Sinan is investigated with an analytical approach depending on a modular system. Existence of a modular system in double-arcaded portico of Sinan Mosques, which was built at different periods, has been investigated and depending on plans of these mosques, the differences and similarities in the formation of the porticos have been analyzed by comparison. Keywords: Mimar Sinan, mosque, double-arcaded portico, modular system, module. Anahtar Kelimeler: Mimar Sinan, cami, cift revak, moduler sistem, modul.