Human isolates of Salmonella dublin were reported to the Centers for Disease Control, Atlanta, 103 times in 1980, as isolation rate nearly twice that reported in 1979. In 1979 and 1980 S. dublin was isolated predominantly in the western United States, frequently from males (60% of the total), from adults older than 40 years of age (55%), and from blood (37%). Detailed histories were obtained for 39 cases outside of California and Oregon, and 32 cases were matched with 62 age-, sex-, and locality-matched control subjects. We found that persons infected with S. dublin were more likely to have suffered from chronic noninfectious diseases (P less than 0.001) and were more likely to have ingested antacids (P less than 0.01) than their controls. In the case-control study, 21 (66%) of the infected persons were hospitalized and six (19%) died. When exposure to cattle, beef, or dairy products was examined, we found that cases differed significantly from controls only by a more frequent consumption of raw milk (P less than 0.001).