The exposure to vapors from jet fuel under different work conditions was examined in three aircraft squadrons. Exposure measurements were made by charcoal sampling in the breathing zones of 23 randomly selected employees belonging to three different personnel groups. Each person was followed during two consecutive days by long-time sampling and, furthermore, by 15-minute sampling during work operations with possible high exposure. The charcoal tubes were eluted with carbon disulfide, and the hydrocarbons were analyzed with gas chromatography. The geometric mean of both the long- and the short-time exposure was only 1-2% of the corresponding occupational exposure limits. The highest long-time exposure observed was about 25% of the occupational exposure limit, while the highest short-time exposure was about 130% of the corresponding limit. Thus the present long-term exposure to solvent vapor in Swedish aircraft units is low, but infrequent short-time exposure above the present limit may occur in some work operations.