Aim: The hepatitis B virus (HBV) is an important healthcare problem. Chronic hepatitis B infection may present with a wide range of manifestations from inactive carrier state to cirrhosis and hepatocellular cancer. Terefore, treatment is very important in chronic hepatitis B. In this study, the treatment results of 199 chronic hepatitis B patients taking entecavir 0.5 mg/day for 48 weeks were evaluated. Materials and methods: Tis study retrospectively evaluated data of 199 treatment-naive chronic hepatitis B patients who were treated with entecavir. Results: Of the 199 treatment-naive chronic hepatitis B patients, 141 (70.9%) were males and 58 (29.1%) were females, and mean age of the whole group was 37.5 ± 12.1 years. HBeAg was positive in 91 (45.7%) and antiHBe was positive in 108 (54.3%) patients. Mean HBV DNA value was 666,449,365.5 ± 2,759,013,996.9 IU/mL, mean ALT value was 112.1 ± 95.7 U/L, and mean AST value was 95.3 ± 71.2 U/L. At week 24 of the treatment, HBV DNA levels were below 50 IU/mL in 56% of the HBeAg-positive and 76% of the HBeAg-negative patients. At week 48 of the treatment, HBV DNA levels were below 50 IU/mL in 79% of the HBeAg-positive and 87% of the HBeAg-negative patients. At week 24, ALT had normalized in 72% of the HBeAg-positive and 79% of the HBeAg-negative patients. At week 48, ALT had normalized in 89% of the HBeAg-positive and 88% of the HBeAg-negative patients. AntiHBe seroconversion was seen in 2 of 91 patients (2.2%), but the loss of HBsAg was never observed. Conclusion: Te 48-week entecavir treatment at a dose of 0.5 mg/day was shown to be efective both for HBeAg-positive and negative patients. © TÜBİTAK.