AIM: To determine the causative agents of spontaneous bacterial peritonitis (SBP) in children with liver disease and ascites in our center.METHODS: During a 2.5 year period, from September 2003 to March 2006, 12 patients with 13 episodes of SBP were studied. In all cases at the time of admission serum albumin and glucose, urinalysis and urine culture was performed. Analysis [white blood cell (WBC) count with differential, albumin, glucose], gram stain, culture by BACTEC method and antibiogram was done on ascitic fluids. Abdominal paracentesis was repeated after 48h of antibiotic therapy for bacteriologic assay. The patients were followed for at least three months in a gastroenterology clinic.RESULTS: There were 7 girls (58%) and 5 boys (42%)with a median age of 5.2 years (range, 6 mo to 16 years). All cases had positive ascitic fluid culture. Gram stain was positive in 5 (38.5%) of them. The isolated organisms were S. pneumoniae in 5 (38.5%), E. coli in 2(15.3%), S. viridans in 2 (15.3%), and K. pneumoniae,H. influenza, Enterococci, and nontypable Streptococcus each in one (7.7%). All of them except Enterococci were sensitive to ciprofloxacin and ceftriaxone. All ascitic fluid cultures were negative after 48 h of antibiotic therapy.CONCLUSION: S. pneumoniae is the most common cause of SBP in the pediatric age group and we recommend a third generation cephalosporine (e.g., Ceftriaxione or Cefotaxime) for empirical therapy in children with SBP.