During the 8-month period of May to December, 1978, a total of 3,529 blood cultures were taken from Yonsei Medical Center patients and the effect of blind subculture in the initial detection of Salmonella typhi positive culture was analyzed. The blind subculture at the end of 1-day incubation (1-d BS) detected 35.0% of S. typhi positive specimens. All of the S. typhi positive specimens by 1-d BS were a1so macroscopically positive. However, by doing slide agglutination with the growth on subculture plate S. typhi was identifiable tentatively. This saved a day compared to macroscopic examination alone. Therefore the 1-d BS is concluded to be a valuable procedure for the isolation of this organism from blood. For the isolation of S. typhi 7-day incubation was concluded adequete based on the fact that there was only 1 specimen which became positive after over 1-week incubation.