The prototype strain of ECHO virus Type 19 was recovered in 1955 by Ramos-Alvarez and Sabin1,2from an infant with diarrhea. In 1959, Faulkner and Ozere3recovered this virus from the cerebrospinal fluid of a 49-year-old man in Nova Scotia. Since that time, we are not aware of any reports of recovery of ECHO 19 virus from ill individuals. During the period from July, 1960, through September, 1961, ECHO 19 virus was recovered in our laboratory from specimens of 30 patients. This article describes the illnesses of the patients and the laboratory studies of the virus isolates. Methods Patients Studied.— During the period of this study, several population groups were under surveillance for viral diseases. These included children (5 to 18 years of age) in a children's home, infants less than 6 months of age and their mothers in a well-baby clinic, children in a rheumatic fever clinic,