The object of study of the present research topic examines the way in which the balcony evolves in the Athenian Polykatoikia from the interwar period until today. The factors that led to its creation, the necessity of its existence, the changes it underwent and the context in which it is redefined are progressed. At the same time, the coherent relationship of the balcony with the facade and the city is explored, in a flowing situation where one constantly interferes with the other, sometimes in a beneficial and generous way, sometimes violently and radically or completely indifferently and conventionally. These attitudes are developed through a triptych of parameters, which can be regulated and deregulated at the same time, and consist of the institutional framework, architecture and the construction-technological becoming. These three levers of construction activity coexist and interact in a marginal state of formation of the face of the Athenian Polykatoikia that entrains with it, the entire urban landscape. The imprint of this path in the periods of intense reconstruction, the changes of building regulations and the historical events that affected the city and its wider view. Through the presentation of examples and their sequential analysis, an attempt is made to answer questions regarding the importance of the design of balconies for the architect, the qualities they provide to the building itself, the vitality and freedom they offer to users and the importance of them as privately owned outdoor spaces. Finally, it discusses the way of communication that a balcony offers with the city and the horizon and the obligation of its existence in every Polykatoikia building, in a way capable of determining the purchase value of the apartments inside.