To determine if ethylene evolution by plants is correlated with the ozone stress, a range of plants species and cultivars was exposed to varying ozone concentrations. Following exposure, the plants were encapsulated in plastic bags and incubated for up to 22h. The stress-induced ethylene that accumulated in the bag was monitored and correlated with the effects of ozone on plants. The rate of stress-induced ethylene production (slope parameter B) as a function of ozone concentration was used as a measure of plant sensitivity. Applying this ranking scale, ponderosa pine, eucalyptus and soybean were the most sensitive species; holly, squash and marigold were the least sensitive. There was a good correlation between ozone induced stress ethylene production and foliar injury. However, the coefficient of variability associated with the ethylene determination was substantially less than with the visual injury estimate. The production of stress-induced ethylene generally lasted for less than 48 hr following exposure. The measurement of stress ethylene appeared to be a fast, reliable, sensitive and reproducible technique to measure ozone stress on plants.