From March through August 1993, outbreaks of E. coli O157:H7 occurred at four separate Oregon and Washington Sizzler restaurants. These restaurants served meats and seafood entries and featured a large, self-service, salad and food bar with more than 100 items. Consumption of beef or other meats was not associated with illness in any of the outbreaks. The locations having outbreaks included: Grants Pass, Oregon (Mar.); North Bend, Oregon (Mar.); Corvallis, Oregon (Aug.); Seattle, WA (Aug.), Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal. Cross-contamination from beef within the independent restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks.