||This paper aims to investigate changing patterns of commercial centres in Istanbul. In order to evaluate the different patterns, their locations on urban macroform and spatial characteristics such as density, compared with their accessibility values. Space syntax method is used to measure the accessibility of each street in urban transportation network via calculating global and local integration of commercial centres. Calculated global integration values are between 0, 03 and 0, 18. Local integration values ranging between 0, 3 and 2, 17. Traditional and modern commercial centres of Istanbul can be classified into three spatial patterns: While traditional centres have circular or linear pattern, modern centres represent a point pattern which rise on third dimension. The traditional centres have the highest values of local integration although they are not most integrated areas of global integration map. On the other hand modern centres are concentrated in most integrated areas at local and global scale of Istanbul metropolitan area. These most integrated areas have more importance with their historical background and spatial characteristics than the periphery of Istanbul. Although traditional and modern centres aim to serve whole Istanbul and contains similar functions, in traditional centres land use density is homogenous with their environment but modern commercial centres concentrates on nodes with higher density than their surroundings. Location choices of modern centres result in overload to these areas by increasing density. This research indicates the potential problems of new commercial centres located in densely settled and historical areas which should be taken into consideration by municipalities and investors.