Background:Hepatitis B virus (HBV) and HIV coinfection is associated with risk of progression to chronic liver disease. We assessed liver stiffness in HBV-HIV coinfected youths.Methods:A cross-sectional study in HBV-HIV coinfected youths aged 18 to 25 years who received a tenofovir (TDF)-containing antiretroviral therapy regimen for >96 weeks. Measurements included HBV DNA level, HBV serology profiles, and transient elastography (TE). The cutoff for TE results included ≥5.9 kPa for F2-moderate fibrosis, ≥7.4 kPa for F3-severe fibrosis, and ≥9.6 kPa for F4-cirrhosis.Results:From March to December 2016, 15 HBV-HIV coinfected youths with a median duration on TDF-containing regimens of 3.3 years were enrolled. Five (33%) youths had significant liver fibrosis, 3 with F2-moderate, 1 with F3-advanced fibrosis, and 1 with F4-cirrhosis. Other 5 without liver fibrosis had hepatitis B surface e antigen (HBsAg) and hepatitis B surface e antigen (HBeAg) loss. Higher mean alanine transaminase (ALT) was observed among the group with F2-F4 when compared to those with F0.Conclusion:Liver fibrosis was evidenced in HBV-HIV coinfected youths in Thailand. Transient elastography might be considered for those who do not achieve HBsAg loss or have persistent ALT elevation while on treatment.