Abstract： Objective To investigate the efficacy of highly active antiretroviral therapy (HAART) for HIV/HCV co-infection patients. Methods A randomized and double blinded trial was conducted in sixty-three HIV/HCV co-infected patients ( group A) and 62 HIV infected patients ( group B). The group A (study group) was further divided into A1, A2, A3 subgroups randomly by Spw-Pb network data system, and were given three different HAART regimens based on nevirapine (NVP), efavirenz (EFV) and lopinavir/ritonavir(LPV/r), respectively. CD4+ T lymphocyte counts, HIV virus load, glutamate-pyruvate transaminase (ALT) were detected at baseline and at the endpoint of study (48 weeks). SPSS 13.0 was used for statistical analysis. One-way ANOVA and LSD-t tests were performed. Results After 48 weeks treatment, HIV RNA became negative in 59 patients of group A (59/63, 93.7％ ), while that in group B was 61 (61/62, 98.4％ ) (x2 =0. 159, P ＞ 0.05 ). CD4+ T lymphocyte count in group A was (208 ± 77 )/μL, which was significantly lower than that in group B (263 ± 78)/μL (t =-2. 759, P = 0. 008 ).ALT level in group A was (57 ±49)U/L, which was significantly higher than in group B (31 ± 14) U/L (t = 2. 027, P = 0.047). CD4 + T lymphocyte count in group A3 was significantly higher than that in A1 (t=-2. 191, P =0.045), while ALT level in A1 was much higher than that in subgroups A2 and A3 ( t = 2.568 and 2.478, P ＜ 0. 05 ). The incurrence of drug-induced hepatitis in HIV/HCV co-infected group was much higher than that in HIV infected group (55.5％ vs. 27.4％, x2 = 10. 182, P = 0.001 ).Conclusions HCV co-infection in HIV patients shows no impact on virological response to HAART, but the immunological response is poorer. Hepatotoxicity is common among patients receiving HAART, especially those who are receiving NVP containing regimens. LPV/r based regimens are recommend for HIV/HCV coinfected patients.