Foodborne botulism is a rare, potentially fatal paralytic illness caused by eating food contaminated by Clostridium botulinum toxin. It occurs most often as a single case not linked to others by a common food source. As a result of improvements in food canning, when outbreaks do occur, they typically involve fewer than five persons. During October 2-4 2011, eight maximum security inmates at the Utah State Prison in Salt Lake County were diagnosed with foodborne botulism. An investigation by Salt Lake Valley Heath Department, Utah Department of Health, and CDC identified pruno, an illicit alcoholic brew, as the vehicle. The principal ingredients in pruno are fruit, sugar, and water. Many additional ingredients, including root vegetables, are sometimes added, depending on the availability of foods in prison. A baked potato saved from a meal served weeks earlier and added to the pruno was the suspected source of C. botulinum spores. Many of the affected inmates suffered severe morbidity, and some required prolonged hospitalizations. Knowing the link between pruno and botulism might help public health and correctional authorities prevent future outbreaks, respond quickly with appropriate health-care to inmates with acute descending paralysis and/or other symptoms, and reduce associated treatment costs to states.