To achieve its political strategies related to people welfare, any country has to make a great effort. In addition, the sustainable economical and social development require strong environmental management. In Rwanda, one of developing countries, urbanization is a continuous process and it very important to identify areas that may be threatened due its growth such as wetlands. The government of Rwanda erected environmental law, policies and regulations to be implemented from the country level to the local level with a view of sustainable protection of all environmental features including wetlands. This research is aiming at assessing the impact of continuing urban encroachment activities in wetlands surrounding Butare town in view to propose GIS implication in decision making for sustainable urban growth. To reach the objective, the spatial evolution of Butare Town was examined, urban encroachment activities carried out on wetland resources were identified and located, risks encountered by wetlands were assessed and alternative solutions were suggested by highlighting how spatial information can positively contribute in better decision making process for wetlands protection.