Importance of security and sense of peace is a one of the most important factors of urban environment. Therefore, the necessity of security in urban spaces has caused the emergence of authentic theories like Defensible Spaces and Crime Prevention through Environment Design (CPTED)*. In this paper, various literatures related to defensible space theories have been reviewed and the related keywords have been defined. Then, the role of defensible urban spaces as a social capital in the reduction of urban crimes is examined. Further, condition of defensible spaces in traditional Iranian cities has been studied with reference to the city of Isfahan. The research method is based on data and documents collected through field survey.The conclusion justifies the precedent of defensible space, in design and planning, as well as shaping historical cities. Safe and secure spaces which support social capital concept, under public surveillance and collective responsibility, works as an important aspect in reducing crimes hence; bringing about a state of stable urban security.
