Background/Aims: To reveal possible factors predicting the effect of adefovir dipivoxil (ADV) treatment on chronic hepatitis B (CHB) and optimize the utilization of ADV. Methods: In total, 168 treatment-naive CHB patients were enrolled, including 117 hepatitis B e antigen (HBeAg)-positive patients and 51 HBeAg-negative patients who met the inclusion criteria. All patients were treated with ADV 10 mg per day for 48 weeks. Multiple logistic regression analyses were used to investigate baseline factors, and responses at weeks 12 and 24 were analyzed as predictive values. Results: Multiple regression analyses showed that baseline HBeAg status and HBV DNA levels significantly affected the virological response (VR) (p<0.05), baseline ALT levels were an independent predictor of serological response (SR) (p<0.05) and the body mass index (BMI) may affect the biochemical response (BR) (p<0.05). There was a statistically significant difference in the VR and SR between patients with a primary nonresponse (PNR) at week 12 and those with a VR at week 12 (p<0.01). Additionally, the VR was significantly different between patients with HBV DNA lower than 10(3) copies/nnL at week 24 and those with greater than 10(3) copies/mL (p<0.01). Conclusions: Patients with negative HBeAg, lower HBV DNA levels and higher ALT values at baseline are more suitable for ADV treatment, whereas patients with lower BMIs may be more amenable to ALT normalization. Adjustments for treatment strategy should be considered if PNR at week 12 or HBV DNA >= 10(3) copies/mL at week 24 is observed. (Gut Liver 2011;5:478-485)