The charts of 100 patients with established diagnoses of glioblastoma multiforme (GBM) provided the data base for a descriptive study of patients' exposure to herbicides. The study focused on place of residence and occupation during the year prior to diagnosis of GBM. Although subjects reported residences in 33 of the 75 counties in Arkansas, more than one-third of the sample came from just 3 counties in which rice, cotton or wood products are produced. These industries were reported as the occupations of almost one-third of the sample for whom occupations involved a risk of herbicide exposure. The findings of this study add to the epidemiological profile of those at risk for GBM and underscore the need for assessment of residence and occupation on a consistent basis when counseling patients and providing health education.