At least 565 cases of hepatitis A were associated with an outbreak at the Chi Chi’s Restaurant in Monaca, Pennsylvania, in 2003. There were 128 hospitalizations and three deaths. As a result of exposure to the restaurant food or outbreak cases, more than 9,000 persons were given an injection of immune globulin to prevent hepatitis A. Numerous secondary illnesses occurred when infected persons who had eaten at the restaurant infected their close contacts. This outbreak, and concurrent outbreaks, were associated with eating raw, or undercooked, green onions that had been grown in Mexico and served in restaurants.