The thermogravimetric behavior of four cereal straws (wheat, barley, oats, and rye) at three heating rates (10, 20, and 50°Clmin) in air was examined. The thermal degradation rate, the initial degradation temperature, the active and passive pyrolysis zones, and the residual weight at 600°C were determined. Increasing the heating rate increased the thermal degradation rate and decreased both the initial degradation temperature and the residual weight at 600°C. The higher the cellulosic content of the straw, the higher the thermal degradation rate and the initial degradation temperature. Also, higher ash content in the straw resulted in higher residual weight at 600°C.