This study was undertaken to assess the potential of two types of improved cookstoves to reduce indoor air pollution in African homes. An ethanol stove, the CleanCook, was tested in three locations in Ethiopia: the city of Addis Ababa and the Bonga and Kebribeyah Refugee Camps, while a wood-burning rocket stove, the Gyapa, was evaluated in Accra, Ghana. In both countries, kitchen concentrations of PM2.5 and CO, the two pollutants responsible for the bulk of the ill-health associated with indoor smoke, were monitored in a before and after study design without controls.