Chronic exposure to aircraft noise elevated psychophysiological stress (resting blood pressure and overnight epinephrine and norepinephrine) and depressed quality-of-life indicators over a 2-year period among 9- to 11-year-old children. Data collected before and after the inauguration of a major new international airport in noise-impacted and comparison communities show that noise significantly elevates stress among children at ambient levels far below those necessary to produce hearing damage.