Emissions of SO2 and NOx from U.S. pulp and paper mills were estimated for calendar years 1980,1985 and 1990. Questionnaires were used to obtain mill-specific information on fuel use, coal and oil sulfur content, SO2/NOx control technology performance, and relevant production-related parameters. Total estimated SO2 emissions declined from 875,000 tons in 1980 to 600,000 tons in 1990, while NOx emissions increased from 274,000 to 305,000 tons. Paper production increased nearly 30 percent from 1980 to 1990.