Abstract: Objective To explore the damage of mitochondrial DNA of the kindey induced by lamivudine (LAM) and adefovir dipivoxil (ADV) combined therapy in rats. Methods Forty healthy Sprague-Dawley rats were randomly divided into four equal groups and treated by oral gavage with ADV [40 mg/(kg·d)], LAM [300 mg/(kg·d)], ADV [40 mg/(kg·d)] + LAM [300 mg/(kg·d)], or saline (equal volume) for 8 weeks. DNA of the kindey was purified from each sample and the mitochondrial DNA (mtDNA) content of the kindey was monitored by quantitative real time PCR. At the same time, the levels of serum creatinine and urea nitrogen were deteced. One-way ANOVA, the LSD t-test and Dunnett’s T3 were used for data. Results Compared with blank control group, the mtDNA content of rats treated with LAM group, ADV group and ADV ＋ LAM group significantly decreased (1.00 ± 0.00, F = 63.72, P ＜ 0.01), which were 0.79 ± 0.12, 0.59 ± 0.13 and 0.42 ± 0.89, respectively. Among them, the ADV group was lower than LAM group (P ＜ 0.01) and the ADV ＋ LAM group was the least (P ＜ 0.01). The levels of serum creatinine and urea nitrogen showed no statistically significant difference. Conclusions After continuous dosing 8 weeks, the mitochondrial DNA content of the kindey was declined with the three treatment groups. And the ADV ＋ LAM-treated rats had the greatest reduction. The rats of ADV combined with LAM have the most serious injury of mitochondria DNA.