In 2009 the Food and Drug Administration (FDA) estimated that its shell egg rule would reduce illness from Salmonella Enteritidis (SE) by about 79,000 cases annually (37%), with a range from about 30,000 to 191,000 cases avoided. I assess the effectiveness of this rule, which requires farmers who sell eggs to adopt SE control measures, by comparing illness from SE with illness from other Salmonella serotypes, using a differences-in-differences approach. The data reject the hypothesis that the rule reduced illnesses by FDA’s best 2009 estimate, but do not reject a hypothesis of no effect. The percentage of young broilers that test positive for SE has a modest effect on the incidence of human cases of salmonellosis caused by SE. Recent literature offers two other reasons to adjust FDA’s prospective 2009 calculations. One adjustment would follow the Centers for Disease Control’s use of a lower multiplier to infer the total number of (unobserved) cases of illness from those confirmed by positive lab tests. A second adjustment would lower the average cost of Salmonella cases, by recognizing lower risk of severe sequelae. These adjustments and the new retrospective assessment of the effectiveness of the rule together suggest that the benefits of FDA’s egg rule may be a small fraction of the prospective estimate of benefits, and less than the prospective estimate of costs. I conclude with some policy recommendations to make food safety regulations more effective.