Chronic severe hepatitis B (CSHB) is a critical clinical syndrome with a high mortality rate in China. The prognostic value of neutrophil to lymphocyte ratio (NLR) which is simple, low-cost, and useful inflammatory marker for hepatitis B virus (HBV)-infected patients is largely overlooked and without further exploration. This study assesses the association of NLR with prognosis of chronic hepatitis B (CHB) and CSHB patients. Two hundred and eighty subjects, including 79 with chronic hepatitis B (CHB) and 67 with chronic severe hepatitis B (CSHB), and 134 healthy individuals were retrospectively recruited into this study. Blood samples were collected to conduct liver function, prothrombin time activity (PTA), international normalized ratio (INR), HBV DNA measurement, and routine hematological testing. All patients were followed up for at least 3 months. NLR values in patients with CSHB (4.984 ± 3.608) and CHB (2.020 ± 1.182) were significantly higher than those in healthy control (1.638 ± 0.601) and patients with CSHB had the highest NLR values than CHB and healthy control. Increased NLR values were clinically associated with severe liver disease and higher mortality rate. NLR was found to be an independent predictor of mortality in multivariable Cox Regression models (HR = 3.912, 95%CI: 1.587-9.640, P = 0.003). NLR values are significantly increased in CHB and CSHB patients with the severity of liver disease. Moreover, NLR value is an independent predicting factor for the mortality rate in HBV-infected patients.