Background and study aim: Spontaneous bacterial peritonitis (SBP) is mainly diagnosed by ascitic polymorphonuclear (PMNL) leukocyte greater than 250/mm³. We intended to assess ascitic homocysteine and calprotectin for SBP diagnosis. Materials and methods: In our study, we collected ascitic fluids from 70 patients with liver cirrhosis (46 SBP plus 24 non-SBP according to PMNL>250 cells/mm³). Complete blood count, alanine aminotransferase, aspartate aminotransferase, serum albumin, total bilirubin, prothrombin time, INR, and serum creatinine were measured. Ascitic fluid sample was taken for chemical analysis, homocysteine was calculated in ascites by human homocysteine enzyme-linked immunosorbent assays (ELISA) kits and calprotectin was measured in the ascitic fluids using available human calprotectin enzyme-linked immunosorbent assays (ELISA) kits.                            Results: SBP patients had considerably greater ascitic homocysteine levels than non-SBP (5.66± 7.15 vs. 2.97±.61 μmol/l) P=0.001. Homocysteine at a cut-off of 3.6 μmol/l had 91.7% specificity, 69.9% sensitivity, PPV 94.1% and NPV 61.1% for SBP diagnosis (area under the curve: 0. 754). SBP patients had considerably greater ascitic calprotectin than the non-SBP (182.98± 76.27 vs. 118.1± 27 ng/mL) P=0.000. Using a cut-off 142 ng/mL, calprotectin had 91.7% specificity, 71.7% sensitivity, PPV 94.2% and NPV 62.9% for SBP diagnosis (area under the curve: 0.768). Conclusion: We found that ascitic homocysteine and calprotectin can be suitable diagnostic markers for SBP diagnosis.