The addition of new modern layers to the historic urban settings is a significant issue in conserving the historic area's characteristics. Thus, a method of evaluation for modern buildings built in historical areas is being devel oped. The objective includes assessing the maintenance of the historic area's qualities and designing qualified modern buildings. These two issues were evaluated by assessing the example of İstanbul Drapers and Yard Goods Bazaar, İMÇ blocks. First, historical house settlements in the construction area of İMÇ (1933) and then characteristics of İMÇ blocks (1967) were analyzed. In terms of mass proportions, the position of courtyards, circulation areas, street and square relations, and vistas, site plan organizations from 1933 and 1967 were compared, while the proportions and architectural details of the façades were compared. The assessment criteria for the evaluation of modern buildings and their impact on historical areas were determined based on international preservation standards and charters. The conservation criteria include respecting the qualities, vistas, and landmarks of existing historic structures, being recognizable and reversible, responding to the demands of the area, and providing new views, juxtapositions, and textures. Modern heritage criteria include technical, land use, aesthetic, historical, socioeconomic, intangible, canonical, and reference qualities. As a result, it is seen that the İMÇ blocks were designed in harmony with the environment and increased the spatial quality of the area. Even though the İMÇ blocks are large-scale due to architectural constraints, the orientation of the blocks, the placement of courtyards leading to the Süleymaniye Mosque, and the transverse and longitudinal continuous circulation between the blocks respected historical texture. Despite the size of the masses, their heights and architectural elements are consistent with the traditional house layout.