Appropriate and sustainable municipal wastewater treatments plants -WWTP- are strongly required in developing countries which face both sanitation problems and poverty. Anaerobic digestion, as a leading technology that generates value added products (i.e. bio-energy, nutrients and water for reuse) has proved to be suitable in those countries, which are mostly placed in tropical and subtropical regions with temperatures higher than 20 °C. Latin America is the region with the highest number of anaerobic WWTP, being the UASB reactor the most common technology for municipal wastewater treatment. Onca WWTP (Belo Horizonte, Brazil) is an example of a large scale implementation, showing that UASB is a stabilized technology with COD removal efficiencies ranging from 65 % to 80 % and HRT between 6-10 hours. However, further research is highly needed in order to improve and upgrade the existing treatment methods; so as to achieve technological solutions that prove to be environmentally harmless and suitable to each particular socio-economic and cultural condition. This work is aimed at analyzing and discussing the anaerobic treatment of domestic wastewater issues and its application perspectives at both small and large scale in developing countries.