Little information is available about medical complaints after marathons held in cool weather. To obtain such information medical records were maintained on every runner requesting medical attention after the Bostonfest Marathon on Oct 30, 1983. One hundred sixty-four (11.5%) of the runners finishing the race requested medical attention at the finish line. Men and women requested attention with equal frequency, but younger (20 to 30 years old) and faster (finishing in less than 3:00) runners sought medical attention more often than the older and slower runners. The complaints and symptoms of runners after the race were similar to those of runners following warm-weather races.