A method for estimating long term exposure of construction painters to mixed solvents from questionnaire data was described. A total of 118 construction and maintenance painters from the Boston (Massachusetts) District Council of the International Brotherhood of Painters and Allied Trades were given a solvent exposure history questionnaire in which the subjects were asked to estimate their average application rates, percentage of time spent actually painting, and respirator uses, both over the past year and over their working lifetime. The data were analyzed in order to calculate an exposure index. The exposure index provided an estimate of the solvent vapor to which a painter was exposed by inhalation. The index was a weighted average of the total number of gallons of paint used per year minus the fraction that could be absorbed by a respirator. The statistical weights were based on the method of application (spraying, rolling, or brushing) and the type of ventilation present. Estimates of solvent exposure among different types of painting were as follows: sprayers, 13527 gallons per year (gal/yr); rollers, 4093gal/yr; and brushers, 1192gal/yr. The fractions of solvent vapor absorbed by respirators were 0.55, 6039gal/yr for sprayers, 4053gal/yr for rollers, and 1188gal/yr for brushers being available for inhalation. The exposure index was found by statistical analysis to be relatively insensitive to the underlying assumptions. The authors conclude that the exposure index appears to provide a useful relative estimate of exposure to organic solvent mixture vapors. These estimates could be used as dose surrogates in epidemiological studies.