Post-harvest application of acetaldehyde vapors to blueberries, tomatoes, and pears led to the enhancement of the fruit sensory quality including an increase in the sugar content, sugar-acid ratio, and flavor changes judged to be acceptable by test panels. Applied ethanol vapors led to similar but limited enhancement of fruit sensory quality. Comparative applications of ethylene were more effective in stimulating changes in the background color, including an increase in the total carotenoid content in tomato and .anthocyanines in blueberry. Ethylene, however, had little or no effect, and occasionally led to deleterious changes in the fruit sensory quality. Acetaldehyde and related volatiles may be important in the development of fruit sensory quality, as occurring normally during ripening, or as a post-harvest application for the improvement of fruit sensory quality.