Grant County, Oklahoma, residents attending a Christmas luncheon December 4 reported becoming ill later in the evening and early the next morning. A retrospective cohort study by Oklahoma health department officials determined the illness was likely due to consumption of turkey. The turkey was sent to the Public Health Laboratory for analysis, and found to contain Clostridium perfringens. This bacterium was also found in stool samples from case-patients. Both samples were evaluated further and found to produce enterotoxin A, and be indistinguishable genetically using pulse-field gel electrophoresis. The health department determined a lack of temperature control of the turkey allowed for the growth of C. perfringens.