A 30-month study is reported of an epidemic of salmonellosis involving 46 newborn infants and 34 older individuals who were contacts and became carriers. A total of 80 persons was involved, all having positive stool cultures for Salmonella sp. (type Oranienburg). Of the total number of infants delivered during the epidemic, the 46 infected infants established an attack rate of 20%. The additional 34 older individuals who were carriers were contacts of the infected infants. The mechanics of contact or mode of pattern of spread could not be completely determined. In the newborn infants response to this infection varied. One infant died, 7 were acutely ill, 33 had symptoms of grossly abnormal stools, 5 had asymptomatic infection and were diagnosed by positive stool cultures alone. With one exception, the older individuals all were asymptomatic and were diagnosed by positive stool cultures. Serologic confirmation of the presence of this specific infection was established by determinations of specific antibodies. These were positive in 9 of 10 infants. In the older individuals, antibody agglutinations were positive in seven of eight so studied. Of the 33 infants followed, all became carriers and at the end of 30 months, cultures of stools of 30 of the total number had become negative for Salmonella sp. (type Oranienburg) and 3 remained positive. Of the 22 older individuals followed, all had cultures negative for Salmonella sp. (type Oranienburg) at the end of 13 months. Therapy was prescribed in six acute cases and all of these patients recovered. Experimental therapy for the carrier state resulted in failure in all cases. A comparison of the group of 20 infants not treated suggested that stools of the untreated patients cleared spontaneously more readily than those who were treated.