This paper describes emission factors for several gaseous and particulate matter emissions from burning chaparral fuels found primarily in the southwestern United States. Measurements of the smoke were taken for flaming and smoldering combustion phases by suspending sample packages over test fires of about 0.5 hectares in size. The mean emission factor for total particulate matter was 15.2 g/kg, a factor of two greater than the respective value of 7.2 g/kg for particles less than 2.5 micrometers in diameter. Emission factors for carbon monoxide were lower for the burns of chaparral fuels than for logging slash burned in the Pacific Northwest. Concentrations of other trace materials contained with the PM2.S were also much higher in smoke from chaparral fuel fires. For example, lead made up nearly 0.34 percent of the PM2.5 for the chaparral but was less than 0.1 percent for the logging slash fires. Measurements were also taken of temperature, vertical velocity, and carbon mass flux within the convection columns above the burn areas.