Currently, Vietnam is one of Cambodia's key trading partners and its role is steadily growing. During 2000-2016 the share of Vietnam in the volume of foreign trade of the country almost doubled. It became possible to achieve such impressive results of the mutual trade growth largely due to a wide practice of using both countries advantages of cross-border trade, which accounts for 80-90% of mutual trade. Cross-border trade between two countries has overcome several stages of development -from the level of self-organization and self-government to the development of state programs and the achievement of interstate agreements, which, in fact, have become the basis for regional policies to boost the economic development of the Great Mekong subregion, as well as backward frontier territories, with the subsequent creation of special frontier trade zones. Cross-border trade promotes economic development of border regions, foreign trade of the country as a whole and serves as a stimulating factor for the development of international integration processes. At the same time, it certainly has its negative consequences. It’s often "suspected" of having informal practices. And these "suspicions" are confirmed. In the border areas, smuggling and fraud have always existed and are still widespread. This report assesses the scale of cross-border trade, its organization, structure, and weighs the positive and negative consequences.