Plastic waste has been identified as a major environmental issue during the last few years. According to estimations approx. 8 million tons of plastic wastes are entering the ocean every year. A major share of this amount is originating in the countries of Southeast Asia and rivers are an important source of marine litter, because they transport waste dumped into rivers or released from dumpsites by flooding. The Mekong River belongs to the 10 most important river sources of marine litter. Improving the financial sustainability of waste management systems and introducing systems of waste prevention, collection, sorting and recycling is key to improve the situation.