Enteroviruses were isolated from 14 of 31 frozen serum specimens obtained from hospitalized patients with enterovirus infection, which had been previously documented by recovery of virus from stool, throat, or cerebrospinal fluid (CSF). Virus was detected in 71% of the positive sera within 3 days of specimen inoculation and serum virus titers ranged from 1.0 X 10(1) to 9.2 X 10(3) plaque-forming units/ml. The data suggest that blood cultures may be useful in the diagnosis of acute enterovirus disease and that use of RD and BGM cells may improve the speed and rate of virus recovery.