To determine the pattern of exercise and associated adverse events, including injuries, a mail survey was conducted on participants in the 1980 Peachtree Road Race Study for whom we were able to obtain current addresses. A total of 535 persons responded, 326 men and 209 women, representing 72% of those with identifiable addresses. Although only 56% of respondents reported that they were still running in 1990, 81% reported that they were still exercising regularly. The cumulative probability for continuing to run was 0.71 for men and 0.56 for women. Injury (31%) was the chief reason given by men for stopping permanently. For women, 28% stopped because they chose another form of exercise. Fifty-three percent of respondents had at least one injury during the 10-yr interval. The probability of experiencing an injury was associated with higher weekly mileage. The knee was the most frequently injured site. Thirty-nine percent of women and 35% of men reported being verbally assaulted. Approximately 10% of persons were hit by thrown objects or bitten by a dog. In a group of recreational runners, almost half had stopped running 10 yr later, but over 80% were still physically active. Many runners sustain injuries or suffer hazards related to their exercise.