The purpose of this research is to identify the planning principles for the capital city of Islamabad in Pakistan located in the homogeneous cultural area known as Punjab region, during the late period of the Modern Movement. The establishment of new cities in Indian regions created the possibility to observe physically some solution of late modernism theories. Nowadays, it is possible to verify their positive or negative relapses and contributions along with the critical analysis of existing literature made by contemporary researchers. They meditate on the theoretical improvement that a recent planned city like Islamabad could give towards the contemporary architectural discipline in a defined region of a developing country. In addition to these aspects, this study will focus the attention on the spreading of contemporary formal and informal settlements that are nowadays supposed to be in a critical point; past and actual planning policy and the differences of urban growing in strict planning city like Islamabad and in the more organic old city of Rawalpindi identify two different characters in occupying the free soil and reshaping the city in its physical qualities and social strata. Beyond the diagram system developed for Islamabad by Constantinos Apostolou Doxiadis, based on the linkages between new way of life with the presence of machines in urban context and the preservation of community identity, is it possible to think about planning and pluralism in the city of Islamabad? Could the studies of traditional cities play a role in shaping the most sustainable community? These questions are investigated having qualitative nature of the data that reminds us to be careful with any conclusions drawn and to use this research only to lead further studies.