Abstract “Tactical urbanism” is a spontaneous - temporary change to the urban spaces, mainly squares, carried by many new activities and uses. However, there is a major roles for street vendors in utilization these spaces as a way of applying tactical urbanism phenomenon. The aim of this paper is to point out the spontaneously unplanned practices that have been carried out by inhabitants, individuals and low cost activities owners, which runout “Tactical urbanism” principles, and its utilization for the main squares in Greater Cairo Region (G.C.R.). The paper question, mainly, the problematic misallocation of uses and activities that generate the street vendors’ roles in main squares utilization regardless the government actions in controlling their spread as in Ramses square in G.C.R. CBD. Finally, the paper tests the principles and the approach of tactical urbanism to solve the street vendors’ problem by a solved example, in Egyptian urban fabric, to assess how it was successful or what was needed instead.