Salmonella somatic antisera for groups A to E were purchased from four commercial producers directly by the Center for Disease Control (CDC) and indirectly through two hospitals. CDC specifications and methods were used to evaluate antisera shipped directly to CDC. To assess the performance of the products under simulated user conditions, we used the commercial antisera purchased indirectly through the hospitals to group coded cultures. Of the 23 antisera ordered by CDC and the hospitals, the CDC received all 23, a large medical complex received 20, and a private hospital received 9. Similar results were obtained with producer and CDC test methods. Forty-five different lots of antisera were evaluated, of which 20% did not meet CDC specifications. The CDC specifications and latest revisions are discussed.