Prevalence of drugs in fatally injured obese pilots involved in aviation accidents has not been evaluated. Therefore, toxicological findings in such pilots (body mass index greater than kg/m2) were examined in a data set derived from the Civil Aerospace Medical Institute's (CAMI's) Scientific Information System for 1990-2005. Aeromedical histories of these aviators were retrieved from the CAMI medical certification and toxicology databases, and the cause/factors in the related accidents from the National Transportation Safety Board's database. In 311 of the 889 pilots, carbon monoxide, cyanide, ethanol, and drugs were found, and glucose and hemoglobin A1c were elevated. Of the 889 pilots, 107 had an obesity-related medical history. The health and/or medical condition(s) of, and/or the use of ethanol and/or drugs by, pilots were the cause/factors in 55 (18 percent) of the 311 accidents. Drugs found were primarily for treating obesity-related medical conditions such as depression, hypertension, and coronary heart disease. Abstract published by arrangement with John Wiley & Sons.