Indoor air pollution, caused by the combustion of four biofuels (fuelwood, dung cakes, agri-residue, and a mixture of fuelwood and dung cakes) in a traditional and an improved mud cookstove (Sugam-II), has been studied. The concentrations of three gaseous pollutants (CO, NO2, HCHO) were measured at three different positions in the indoor environment. Results are presented and discussed.