In this article, the author analysed an algorithm of successful cooperation: 20-10 – the 20th Lower Danube Euroregion anniversary and 10th ACTEDJ anniversary. Twenty-one years passed since the Euroregion set up, which included eight members – public administrations from Braila, Galati, and Tulcea (Romania), Cahul and Cantemir (Moldova), Odessa and Reni (Ukraine), with a total geographical area of 53,460 km?; it benefited a community of four million inhabitants and implemented a project portfolio of over 500 million Euros in development funds. These projects have been dealing with issues of connectivity (rehabilitation of roads, airport infrastructure, etc.), tourism, health, cultural and economic development, and one common executive management structure was set up in 2009: the Association of Cross-border Cooperation “Lower Danube Euroregion” (ACTEDJ) with its headquarters in Galati, Romania.