Abstract Background Spontaneous bacterial peritonitis (SBP) is a serious complication of liver cirrhosis and is defined as infected ascites in the absence of any recognizable secondary cause of infection. One of the possible mechanisms of developing Spontaneous bacterial peritonitis is bacterial translocation. Aim of the Work The aim of this study is to assess the role of ascitic endocan levels in the diagnosis of SBP in decompensated cirrhosis. Patients and Methods 90 cirrhotic patients with ascites were included in the current study and divided into 2 groups: SBP group with positive ascites culture or with an AF PMNL count ≥ 250/mm3 included 45 subjects. Non SBP group with negative ascites culture or with an AF PMNL count > 250/mm3 included 45 subjects. In the SBP group, the mean age was 58.77 years with male predominance (68.8%).As regard to Non SBP group, the mean age was 59.31 years with male predominance 57.8%. Results There was a statistical significant difference in between SBP group and Non-SBP group as regard to Platelets, ALT, ascetic Total leucocyte count, Protein and LDH. The most common presentation in SBP group was Upper GIT bleeding and Abdominal pain and the most common organism detected in the culture of ascitic fluid Escherichia coli (80%) followed by Streptococcus viridans (15.5%). Ascitic Endocan level was significantly higher in SBP group than Non-SBP group with P < 0.001. The sensitivity and specificity of Ascitic Endocan in detection of SBP were 84.85% and 82.69% respectively. There was a positive significant correlation in between Ascitic Endocan level and ALT, AST, bilirubin, CRP, Child class, MELD score, Blood Leukocytes and TLC (cell/mm3) in ascitic fluid in SBP group. The significant predictors of bad outcome in patients with SBP were higher ascitic fluid Endocan level, CRP and higher Glucose in ascitic fluid (mg/dl) levels Conclusion High Ascitic endocan level is common in cirrhotic patients with SBP than in Non-SBP and that means Ascitic endocan is related to the severity of the disease. Ascitic endocan level is an independent risk factor for SBP. High Ascitic endocan level is a significant predictor of bad outcome in patients with SBP. Therefore, measurement of Ascitic endocan level provide a new strategy to more aggressive treatments for high-risk groups. Ascitic endocan level could be used as an inflammatory biomarker for the prognosis of patients with SBP