Rifat Chadirji, as one of Iraq's regionalist architects, played a significant role in the formation of 1950s Iraq's modern architecture. He was a well-known architect in England and the Arabic world through his many projects and publications. However, despite the recognition for his architectural ideology and design works in the Arabic languages, there is almost no global exposure to Chadirji's regional architecture products. Despite the various economic and political troubles Iraq has experienced since the First World War, including the many restrictions from the changing political environments, learning from the works of Rifat Chadirji increases awareness of the local architecture. Much literature informs that Chadirji, despite undergoing a modern Western architectural education, his architecture reflects the local traces and characters. Therefore, this paper intends to examine buildings designed by Chadirji to reveal the ideology of Architect-Rifat Chadirji in the foundation of modern Iraqi architecture from the 1952s to the 1980s. The study was conducted in the capital city of Iraq, Baghdad, by employing two parts of qualitative analyses, i.e., firstly, for developing a theoretical framework, using content and descriptive analyses from various writings and projects of the subject under study, and secondly, for case studies. Nine buildings were chosen as case studies, within which three were selected for each period. The significance of these findings led to deriving the components of Iraq's Regional Architecture of the 20th Century. The findings will also be a great source of inspiration for the architectural community, the Arab community, and the local Iraqis to continue to explore Chadirji's legacy to make Iraq's modern architecture, their Arab Regional Architecture, their own.