Objective: This study was designed to determine the efficacy and safety of Entecavir (ETV) after 96 weeks treatment in patients with chronic viral hepatitis B (CHB). Methods: Thirty-eight patients were included into the study. The criteria for starting ETV treatment were as follows: elevated ALT levels >upper limit of normal (ULN) two times, with HBV-DNA levels ≥5 log10 copies/ml (≥20000 IU/mL), in HBe Ag positive patients, ≥4log10 copies/ml (≥2000IU/mL) in HBe Ag negative patients and liver damage was confirmed by histopathology (Knodell HAI ≥4 or fibrosis ≥1). Patients were followed up every 12 weeks by virological and biochemical tests. Results: Twenty-four of 38 patients (63.2%) were male. Mean age of patients were 38.6 years, 14 of them were HBeAg positive (36.8%). At baseline, median ALT level was detected as 106.7 IU/ml, median HBV DNA levels were 4.8 x 107 copy/ml, and mean Knodell HAI score was nine. Eleven of 14 HBe Ag positive patients (78.6%) were treatment-naïve. No resistance mutation was determined during treatment. Biochemical responses (BR) at 48th and 96th week were 100% and virologic response (VR) were 57.1%, and 50%, respectively. Serological response (SR) at 48th and 96th weeks were 35.7% and 42.8% respectively. Fifteen (62.5%) of 24 HBe Ag negative patients were treatment-naïve; two patients were detected to have lamivudine resistance mutation. At 48th and 96th week, BR was 95.8%, and 100%, respectively; and VR were 83.3% both. Conclusion: In our study, virologic response was significantly high after two years of therapy with Entecavir in HBe Ag negative patients., Amaç: Bu çalışmada kronik hepatit B hastalarında 96 haftalık Entekavir (ETV) tedavi etkinliğinin ve güvenliğinin değerlendirilmesi amaçlandı.Yöntemler: Kronik Hepatit B tanısıyla 38 hasta çalışmaya alındı. Entekavir tedavisine başlama kriterleri: yükselmiş ALT düzeyleri, (>normalin iki katında fazla), HBe Ag pozitif hastalarda HBV DNA ≥5 log10 kopya/ml (≥20000 IU/ml), HBe Ag negatif hastalarda ≥4 log10 kopya/ml (≥ 2000 IU/ml) karaciğer hasarının histopatolojik olarak gösterilmesi (Knodell HAİ ≥4, fibrozis ≥1). Hastalar 12 haftada bir biyokimyasal ve virolojik testlerle takip edildi. Bulgular: Hastaların 24’ü (%63,2) erkekti. Yaş ortalaması 38,6 yıldı. Tüm hastaların 14’ünde (%36,8) HBe Ag pozitifti. Başlangıç ortalama ALT düzeyleri 106,7 IU/ml, HBV DNA düzeyleri 4,8 x 107 kopya/ml ve Knodell HAI skoru dokuz idi. HBe Ag pozitif hastaların 11’i (%78,6) naivdi. Hiçbirinde direnç mutasyonu yoktu. Biyokimyasal yanıt (BY) 48. ve 96. haftalarda %100, virolojik yanıt (VY) sırasıyla %57,1 ve %50 idi. Serolojik yanıt (SY) sırasıyla %35,7 ve %42,8 olarak saptandı. HBeAg negatif hastaların 15’i (%62,5) naivdi; iki hastada lamuvidin direnç mutasyonu saptandı. Kırksekizinci ve 96. haftalarda sırasıyla BY %95,8 ve %100, VY %83,3 saptandı.Sonuç: Çalışmamızda iki yıllık entakavir tedavisi sonucunda, özellikle HBe Ag negatif hastalarda tedaviye yüksek oranda yanıt sağlanmıştır