Quantifying the exposure of agricultural workers to pesticides is difficult in the face of the heterogeneity of the pesticides used, the variability in methods of application, and the lack of adequate exposure data. This report describes an attempt to estimate long-term dermal and inhalation exposure of bulb farmers by the development of an exposure index. This proposed exposure index consists of generic levels of exposure specific to the method of application, which were derived from databases as well as from field studies. The index is further determined by farm-related parameters such as acreage and number of pesticide applications ascertained from questionnaire responses. A widely used dithiocarbamate mixture served as a marker compound for exposure to other pesticides. Ranking of 127 bulb farmers according to calculated lifetime dermal exposure correlated only moderately to ranking based on duration of exposure, e.g., years of exposure and farm acreage. This finding indicates that the proposed exposure index could provide a useful estimate of long-term exposure to a mixture of pesticides in epidemiological investigations.