Housing production busied the construction industry in Ankara during the 1920s as the small Ottoman town was transformed into the new capital city of the Turkish Republic. To accommodate the rapidly increasing population, alongside traditional houses, new housing types emerged, and ‘apartments’ were introduced for the first time to the new capital city. The transformation of traditional houses into apartments was not direct but gradual with the duality of historicist facades and modernized interiors and with the ensemble of 'traditional' and 'modern' characteristics. With five apartment cases exemplifying this transformation, this article demonstrates that despite the formal characteristics of the 'national' style, the manifestation of modernization began with technical advancements and changes in the spatial configuration of the housing units. This manifestation is presented by analyzing the technical and spatial characteristics of the selected cases as empirical evidence of modernization of the construction industry and the transforming usage schemes in housing due to the changes in the family structure and sociocultural aspects in the daily lives of the inhabitants of the city. With the introduction of the service spaces within the residential interiors via the retrofitting of infrastructure, with transforming polyvalent traditional spaces into 'defined' spaces and by creating hierarchies in residential interiors with publicity-privacy-based spatial configuration, the new houses constructed fulfilled the requirements of newly modernized families of the 1920s' Ankara.