Abstract: Spontaneous bacterial peritonitis (SBP) is a very common bacterial infection in patients with cirrhosis and ascites. In these patients, cytokines as IL-10 are released to blood in response to infection. This study aimed to evaluate serumInterleukin-10 levels in cirrhotic patients with spontaneous bacterial peritonitis and its role in prediction of SBP. We prospectively studied 65 subjects at our University Hospital, The subjects were subdivided into three groups; group I included 20 healthy subjects (control group), group II included 20 cirrhotic patients without SBP and group III included 25 cirrhotic patients with SBP. IL-10 levels in the serum of studied groups were analyzed by ELISA and measured at diagnosis and after resolution for SBP group. A significant difference in serum IL-10 levels was detected between studied groups (P=0.0001) with mean value was higher in cirrhotic patients with SBP than cirrhotic patients without SBP and control group (67.51±34.03 vs 26.50±13.03, 17.08±5.20pg/mL respectively).Furthermore, There was significant decrease in the levels of serum IL-10 after treatment than before treatment (at diagnosis) in SBP group. Serum IL-10 at cut off value (19.4 pg/ml) had high sensitivity, specificity, PPV and NPV (80%, 80%, 90%, and 64% respectively) with AUC was (0.864) and (p=0.0001). IL-10 levels in serum may be related to development of SBP. Serum IL-10 had high sensitivity and specificity in prediction of SBP.