Istanbul city is the center of increasing industrialization in Turkey with proportionally developing problems, such as distorted settlements, and slums, etc. The rapid migration to Istanbul, which is located in the earthquake hazard risk zone, has resulted in a raised population and these structures. Urban regeneration/transformation/planning is expressed as a comprehensive action plan that aims to provide a lasting solution to be economic, physical, social, and environmental conditions of a diverting region to solve the problems in the cities. This paper analyzes the urban transformation process and applications of reinforced concrete (RC) and masonry or mixed masonry-RC buildings in Istanbul within the scope of the urban planning law called "Law on Transformation of Areas at Risk of Natural Disaster" (Law No. 6306 dated 2012). To reach this goal, a total of 400 risky building forms with 150 RC buildings as well as 250 masonry-mixed buildings considered according to Law No. 6306 is compiled and evaluated as risky building data. The general characteristics of the RC and masonry-mixed buildings in Istanbul are determined by a date range of such as 2012-2020. With the results obtained from the paper, significant contributions have been made to the knowledge and technological capabilities at the international/national level.