Istanbul is the largest city in Turkey and is the most important socio-economic, cultural and touristic centre of the country. As the historical capital of three empires, its very rich cultural and social legacy is reflected in its public spaces. Despite its rapid growth and the transformation of its physical and social structures during the second half of the twentieth century, its public spaces still preserve much of their traditional social interactions, a quality which is difficult to find in many industrial cities. The purpose of this paper is to investigate the changes that have occurred through time in the social and physical characteristics of public spaces of the city. In the analysis, some distinguished streets, squares and waterfronts were chosen from different parts of the city and compared and contrasted with their previous and current physical and social characteristics. The results of this study illustrate that location, social and historical backgrounds, accessibility and investments for their redesign have played important roles in the successful transformation of these public spaces.