BACKGROUND: High levels of serum low-density lipoprotein cholesterol are associated with better response to pegylated interferon and ribavirin in hepatitis C virus monoinfected patients. There are no data concerning this topic in HIV/hepatitis C virus coinfected patients in whom lipid disorders are particularly common. OBJECTIVE: To assess the association between baseline lipid levels and sustained virologic response to pegylated interferon and ribavirin in coinfected patients. METHODS: A total of 260 HIV/hepatitis C virus coinfected patients under treatment with pegylated interferon and ribavirin and who had a baseline serum lipid profile were included in this retrospective study. RESULTS: Thirty-eight (24%) patients with genotypes 1-4 and 64 (63%) with genotypes 2-3 achieved sustained virologic response. Forty-nine (44%) patients with serum low-density lipoprotein cholesterol levels 100 mg/dl or more showed sustained virologic response compared with 53 (36%) with lower values [adjusted odds ratio: 2.51; 95% confidence interval: 1.40-4.87; P = 0.003]. This association was independent of the remaining predictors of sustained virologic response which were genotypes 2-3, plasma hepatitis C virus RNA 600,000 IU/ml or less, exposure to at least 80% of the planned therapy and lack of concomitant antiretroviral therapy. The rate of sustained virologic response in patients with genotype 1 and low-density lipoprotein cholesterol at least 100 mg/ml was 31% compared with 17% in those with lower values (adjusted odds ratio: 2.19; 95% confidence interval: 1.04-4.66; P = 0.040). The corresponding figures in subjects with genotypes 2-3 were 73 and 58% [2.71 (0.99-7.46); P = 0.054]. No other lipid was associated with response. CONCLUSION: Higher low-density lipoprotein cholesterol levels predict sustained virologic response to pegylated interferon and ribavirin in HIV/hepatitis C virus coinfected patients. This might be used to improve the rate of sustained virologic response in this setting.