In July 1988, an outbreak of cholera with 71 culture-confirmed cases of biotype El Tor, serotype Ogawa, occurred in a non-endemic area in Mae Sot district, Tak province. Fifty-two cases had diarrhea and 19 had asymptomatic cholera infection. No cases died. Epidemiological investigation revealed a significant association between cholera infection and the consumption of uncooked beef. Increased risk of cholera infection was observed when the incriminated beef was kept at room temperature and consumed later without cooking. The beef was possibly contaminated with V. cholerae O1 from an infected butcher who may have contracted the disease from his foreign worker who was found to have asymptomatic cholera infection. Early detection of the outbreak and rapid identification of transmission source permitted prompt appropriate control measures which, therefore, prevented the outbreak from spreading to other communities. As outbreaks of foodborne diseases, including cholera, have been reported frequently after the consumption of raw food in many parts of Thailand, preventive educational efforts should be directed towards modifying the traditional behavior patterns of consuming raw food among these Thai people.