Background We aimed to investigate whether mean platelet volume (MPV) and platelet distribution width (PDW) are variables determining the severity of liver ibrosis in patients with chronic HBV infection. Methods Patients were divided into two groups with ibrosis scores of 0–2 and 3–6 (according to Ishac scoring system). Whether MPV and PDW were independent variables determining the severity of liver ibrosis score or not was investigated by comparing these groups. Results Of the 111 cases, 74 (66.7%) were male (mean age 37.7±11.6 years). Twenty-two of the cases (19.8%) were HBeAg-positive. Fibrosis scores of 42 cases (37.8%) were≥ 3 and the remaining 69 cases had ibrosis scores< 3 (62.2%). Independent variables determining the severity of ibrosis score were low levels of albumin and mean platelet volume, and high levels of prothrombin time and PDW (Odds ratio (95% conidence interval) and p values were 0.105 (0.018–0.605) and 0.012 for albumin, 0.402 (0.234–0.692) and 0.001 for mean platelet volume, 1.529 (1.183–1.975) and 0.001 for PDW, and 0.924 (0.875–0.976) and 0.005 for prothrombin time, respectively). he sensitivity, speciicity, positive predictive value and negative predictive value of regression model that is established using above mentioned parameters were 88.1, 75.3, 68.5, and 91.7%, respectively (AUC= 0.886, p= 0.0001).