In an effort to improve detection of fastidious organisms, joint fluid aspirates of pediatric patients were inoculated into BACTEC 460 aerobic blood culture bottles, in addition to cultures on solid media. Culture records for the 1988 to 1991 period were reviewed to compare the performance of both methods for the recovery of pathogens. Overall, 216 children underwent a diagnostic joint tap, and 63 specimens grew significant organisms, including Kingella kingae in 14. While both methods were comparable for recovery of usual pathogens, with a single exception, K. kingae isolates were detected by the BACTEC system only. K. kingae appears to be a more common cause of septic arthritis in children than has been previously recognized. The BACTEC blood culture system enhances the recovery of K. kingae from joint fluid and improves bacteriologic diagnosis of pediatric septic arthritis.