Approximately 34,000 Iranians known to have sustained mustard agent exposure during the Iran-Iraq war of 1980-1988 and survived over a decade afterwards were screened for distribution of the most commonly occurring medical problems. In order of greatest incidence, these include lesions of the lungs (42.5%), eyes (39.3%), and skin (24.5%). Within each subpopulation, patients were ranked according to severity of lesions. Twenty-three percent to 37% of patients exhibited at least mild coverage, with 1.5% to 4.5% classed as moderate, and a much smaller population (0.023-1.0%) of the 34,000 patients exhibiting extensive (severe) lesional coverage. These results provide a comprehensive overview of the medical problem most common among mustard victims and could serve as a predictor of the likely impact of these weapons on health status of populations exposed to them during ongoing military conflicts.