An outbreak of E. coli O157:H7 infections was epidemiologically linked to eating hamburgers purchased from a fast food restaurant chain with outlets in Tennessee (2 outlets) and Georgia (1 outlet). Inspection of the outlets failed to find any deficiencies in cooking temperature or procedures, but did identify the potential for ground beef to have cross contaminated other foods. E. coli O157:H7 was never isolated from the hamburgers. It was likely that all contaminated hamburger had been served prior to the detection of the outbreak by public health workers.