Diaspora as a phenomenon has been studied in a number of disciplines, and therefore, it is not surprising that the definitions used vary and generate criticism. Diasporas are considered to be transnational populations living in a country other than their country of origin, but with ties to the country of origin.The phenomenon of diaspora poses challenges but also offers potential benefits to communities in both the homeland and the diaspora. Besides the conceptual analyze, this article claims the role of existing Diasporas on the size, educational structure and concentration of migration flows across different destinations. A large literature in sociology and economics has identified that migrants networks facilitate further migration of people, movement of goods, capital, and ideas across national borders. Also, the study claims increasing the understanding of diaspora networks by reviewing the current literature. The paper illustrates extant theories and research findings, and suggests issues for further research.