The Informal housing phenomenon is one of the dangerous residential challenges facing governments in many cities of the world. Informal housing happens when a crosssection of society tries to solve their housing problems by themselves without government supervision or interference. This stems from their limited financial and cultural abilities, triggering a residential environment requiring sound designing and arrangement. There will not be a final solution to informal housing in sight without addressing the reasons that cause the informal housing phenomenon and ways of handling them. Moreover, internal migration is one of the main reasons for informal housing that researchers agree on. So, this recent research investigates the internal migration phenomenon being one of the reasons for studying and analyzing its volume and direction. This is a first step towards examining the correlation between the informal housing phenomenon and internal migration. This research also deals with the internal migration effect on the demographic properties of informal housing areas by a field study of a number of informal housing areas in Lattakia. This study shows that internal migration is one of the component factors for informal housing, showing its clear effect on the demographic features of informal housing areas.