In 18 of 547 patients who had received nucleoside analogue preparations for 1 year or more, multi-drug resistance was detected, after a median follow-up of 53 months. No patient showed liver failure related to multi-drug resistance acquisition. Multi-drug resistance was associated with entecavir (ETV) therapy in 7 lamivudine (LAM) -resistant patients, combination therapy with adefovir dipivoxil (ADV) in 8 LAM-resistant patients, LAM switching to ETV in 2 patients, and initial ETV administration in 1. For treatment, combination therapy with LAM and ADV was performed. In non-responders, combination therapy with ADV and ETV was employed. In all LAM- and ADV-resistant patients, and the HBV DNA level decreased to 3.0LC/ml or less. However, a similar decrease was noted in 7 (58.3%) of 12 LAM- and ETV-resistant patients. Of the 18 patients, 1 did not respond to combination therapy with ADV and ETV. Therapy with tenofovir disoproxil fumarate (TDF) was required.