At least 565 cases of hepatitis A were associated with an outbreak traced to green onions served at the Chi-Chi’s Restaurant in Monaca, Pennsylvania, in 2003. At least 128 people were hospitalized with hepatitis A infections and 3 people died. 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 infection. Numerous secondary illnesses occurred when infected persons who had eaten at the restaurant infected their close contacts. Several concurrent hepatitis A outbreaks were associated with eating raw, or undercooked, green onions that had been grown in Mexico and served in restaurants.