The traditional markets have played a significant role in the development of historic cities in the Muslim world; they were developed through time in response to socioeconomic and cultural needs of the society. The aim of this study is to investigate the process of formation and working of traditional markets in historic cities of some cities of the Muslim world, in order to suggest some guidelines for their improvement and conservation. A broad range of information was collected from various sources and through a field survey carried out in the selected case study of Casbah city, Algiers. The collected information was analyzed with particular regard to the special character. This study is an attempt to address the important issues that have been raised in the historic cities and it is hoped that it is going to be a significant contribution to the subject of Islamic architecture and urbanism as well as conservation. Detailed conclusions have been arrived at the end and specific suggestions are intended to assist in examining problem in depth and helping in developing sustainable guidelines for the improvement of the current situation in these traditional markets.