The observation that only 42% of the cases of suspected spontaneous bacterial peritonitis at the University of New Mexico, Albuquerque, had positive cultures prompted a change in ascitic fluid culture technique such that a large volume (10 mL in toto) of ascitic fluid was inoculated into blood culture bottles at the bedside. This new method of culture increased the percentage of cases with positive cultures to 91% and decreased the interval between inoculation of the culture and detection of bacterial growth. This is a more sensitive method of culture than the conventional method in detecting spontaneous bacterial peritonitis.