OBJECTIVES: The purpose of this work was to describe illnesses and injuries sustained by campers at summer camps, calculate illness and injury rates, and identify risk factors for camp-related illness and injury. METHODS: A convenience sample of camps selected from the US summer camp population participated in this pilot illness and injury surveillance study. Camps completed weekly reports detailing the number of campers on site and the number of adverse events sustained and provided specific information about each adverse event. RESULTS: A total of 177 camper illnesses and injuries occurred during 122,379 camper-days, with a median rate of 1.15 adverse events per 1000 camper-days. The majority of reported events were illnesses (68.0%), 11.8% of which were communicable and seen in multiple individuals at camp. Of the injury events (32.0%), cut/scratch/scrape were the most common diagnoses (33.3%), followed by fracture (14.6%) and sprain/strain (10.4%); horseback riding and capture the flag were identified as injury-producing activities. CONCLUSIONS: Internet- and telephone-based surveillance systems can be successfully used to conduct illness and injury surveillance among children attending summer camp. Data collected via such systems can be used to calculate illness and injury rates, to describe patterns of illness and injury, and to identify risk factors for camper-related illness and injury. Given the millions of children attending summer camp yearly, a surveillance system such as this can provide the data needed to develop evidence-based prevention interventions to decrease the number of youth whose camp experiences are negatively affected by illness and injury.