BACKGROUND: The neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte-ratio (PLR), and red blood cell distribution width (RDW) are simple indicators of inflammatory status previously established as a severity indicator in distinct disease states. This study aimed to determine the impact of these simple hematologic indices with conventional inflammation markers such as C-reactive protein (CRP) and white blood cells in acute pancreatitis (AP) patients and their relationship with AP risk stratification scores including Bedside Index for Severity of Acute Pancreatitis (BISAP) and modified Glaskow Prognostic score (mGPS) scores. METHODS: This retrospective study was performed in the emergency department of Canakkale Onsekiz Mart University. A total of 171 patients (male/female: 68 [39.8%]/103 [60.3%]) with AP and 59 age and gender matched healthy subjects (male/female: 23 [39%]/36[61%]) as controls were enrolled in the present study. The patients were grouped according to severity and adverse outcomes according to BISAP and mGPS and a comparative analysis was performed to compare the NLR, PLR, and RDW between groups. RESULTS: The mean NLR values of AP patients and control group were 9.62 +/- 6.34 and 2.04 +/- 1.08, respectively (p<0.001), while the mean PLR values of AP patients and control group were 221.83 +/- 122.43 and 83.30 +/- 38.89, respectively (p<0.001). Except from RDW, all the other hematologic indices were found to be elevated (p<0.05 for WBC; NLR, PLR, and CRP) on both mild and severe disease at disease onset. NLR and PLR showed significant predictive ability for estimating serious complications associated with AP. CONCLUSION: The present study showed that NLR and PLR is increased in AP. Moreover, peripheral blood NLR and PLR values can predict disease severity and adverse outcomes associated with AP and can be used as an adjunctive marker for estimating disease severity.