The present paper investigates the role of urban networks in interaction and integration of cities by means of the osister cityo movement. The paper addresses the relationships of oEurocitieso with their osister citieso to highlight the main factors behind the successful relationships. The data and information used for evaluation are based on the extensive survey questionnaires filled out by relevant departments or experts of municipalities in Eurocities. A logistic regression method is deployed to identify the most important factors in the success of sister city relationships. The results of our study show that the existence of any former relation with the sister cities affects the success of the relationship positively. This former relation makes it easier to have a future relation with an economic partnership while shortening the process and accelerating the economic partnership. The results also show that two factors, viz. similarities in urban problems and contributions of Eurocities to their sister cities stimulate the willingness of Eurocities to improve the relationship. The contributions as well as economic benefits provided from the sister city relationship and new business and investment opportunities have emerged as the most important factors in sister city relationship.