The NOAA 12 advanced very high resolution radiometer detected extensive forest fires in boreal Siberia and northern Mongolia during April through October 1998, a year of extremely dry weather, in particular, in the Russian Far East. Analysis of the satellite data has been carried out to estimate the area burned and gaseous emissions to the atmosphere from the point of view of ozone precursors. The fires started in western and eastern Siberia and moved eastward during the summer, until they were concentrated in the Russian Far East, near Sakhalin Island, in the period of July to October. Satellite observations for the fire season and detailed characteristics of terrestrial vegetation in the form of multilayer geographic information systems were used along with published emission factors from similar fires to calculate the gaseous emissions. The total area burned is estimated to be 1.1 107 ha with 350 Tg of biomass consumed and 176 Tg of carbon released into the atmosphere. The carbon released into the atmosphere is calculated to contribute 516 Tg of CO2, 50 Tg of CO, 1.6 Tg of CH4, 1.1 Tg of NMHC, and 9.5 Tg of C particles as smoke. In addition, we estimate that 1.8 Tg of NOx (as NO2) were released.