Background and aim:  A potentially fatal side effect of decompensated liver cirrhosis is ascites. One potentially dangerous consequence in cirrhotic individuals with ascites is spontaneous bacterial peritonitis (SBP). Diagnostic paracentesis is a method used to diagnose SBP, although it is an invasive procedure. Numerous noninvasive markers were investigated in SBP diagnosis. Thus, this study aimed to assess the clinical utility of the noninvasive markers for the diagnosis and treatment response in patients with SBP, namely the lymphocyte monocyte ratio (LMR), mean platelet volume (MPV), and absolute neutrophil count (ANC). Patients and methods: This study included 162 cirrhotic patients was conducted. They were divided into 2 groups, group I included 101 cirrhotic patients with SBP and group II included 61 cirrhotic patients without SBP. ascitic fluid sampling and complete blood count (CBC) including ANC, LMR and MPV were done. Results: There was a significant difference between the 2 groups as regard ANC and LMR (p<0.05). In SBP group there was a significant difference in ANC, LMR, MPV before and after the standard\antibiotic treatment. Absolute neutrophil count had sensitivity 79.21%, specificity 63.93% However, the LMR had sensitivity 91.09 %, specificity 68.85 % and MPV had sensitivity 83.17%, specificity 62.30%. When ANC, LMR and MPV were combined, the sensitivity was 91.10% and specificity was 91.80%. Conclusion: This study suggests that the ANC, MPV, and LMR may be utilized as noninvasive markers for the diagnosis of SBP and prediction of treatment response, enabling prompt detection of SBP to minimize its consequences.