OBJECTIVE:: Few studies have examined the impact of viral hepatitis on bone mineral density (BMD), and none have done so among HIV-infected patients. Our objective was to determine whether viral hepatitis was associated with low BMD in HIV. DESIGN:: A cross-sectional study among 1237 HIV-infected patients (625 with viral hepatitis). METHODS:: Dual-energy X-ray absorptiometry scans of the lumbar spine and femoral neck were obtained. Clinical data, hepatitis B and C status, and markers of bone metabolism were determined at dual-energy X-ray absorptiometry scanning. Multivariable logistic regression examined the association between hepatitis and low BMD (Z-score </=-2.0 at the lumbar spine, femoral neck, or both). RESULTS:: Mean BMD Z-scores were lower among hepatitis-coinfected women at the lumbar spine {-0.15 versus +0.29; difference = -0.44 [95% confidence Interval (CI) -0.65 to -0.23]; P < 0.001} and femoral neck [-0.64 versus -0.39; difference = -0.25 (95% CI -0.44 to -0.06); P = 0.009] compared with HIV-monoinfected women. No differences in mean BMD Z-scores were observed between coinfected and monoinfected men. After adjustment for age, BMI, duration of HIV, antiretroviral use, physical activity, and smoking, viral hepatitis was associated with low BMD among women (adjusted odds ratio 2.87, 95% CI 1.31-6.29) but not men (adjusted odds ratio 1.19, 95% CI 0.74-1.91). Coinfected women had lower mean parathyroid hormone (60.1 versus 68.1 pg/ml; P = 0.02) but similar mean 25-hydroxyvitamin D (19.1 versus 19.6 ng/ml; P = 0.6) and osteocalcin (3.0 versus 3.2 ng/ml; P = 0.8) concentrations than HIV-monoinfected women. CONCLUSION:: Viral hepatitis was associated with a higher risk of low BMD among HIV-infected women but not men.