We compared the BACTEC 9240 continuous-read instrument using Peds Plus/F, Lytic/F, Aerobic/F, and Anaerobic/F media (Becton Dickinson Diagnostic Instrument Systems, Sparks, MD) with and without fastidious organism supplement to conventional centrifugation preparation and plating for the recovery and speed of detection of microorganisms. A total of 908 sterile body fluid specimens were collected and processed, yielding 116 (13%) positive cultures. Of the 80 isolates considered clinically significant, 48 (60%) were recovered by both the BACTEC system and conventional culture, whereas 32 (40%) were recovered by BACTEC only. No clinically significant isolates were recovered only by conventional culture methods. The time to detection for isolates recovered from both sets was faster for BACTEC. It was found that BACTEC, with or without the addition of fastidious organisms supplement, exhibited improved sensitivity for the recovery of microorganisms.