Street art is dynamic concept which has continuous changes. Multidimensional structure of street art allows it to be examined in different fields. Studies on street art mostly focus on what street art is and how it differs from other similar art terminologies. Street art can be defined as any informal artistic practices or artworks performed in public spaces. The aim of the thesis is to reveal how street art affects public space as a matter of urban design. In this context, the thesis aims to investigate the factors transforming public spaces into public places and to examine the quality of the spaces before and after the street art performances through a case study. With this aim, since the concept of street art is a continuously changing phenomenon, the definitions, development and examples of street art are firstly examined. Secondly, what public space is, what makes successful place, what public space means for street art and how street art transforms public space into public pace has been examined. Thirdly, the impacts of street art on different types of spaces are examined in the example of Urla, Izmir. Finally, the impacts of street art on different types of spaces are evaluated and how it should be approached from urban design perspective is described.