Aim: To identify the age at which HCV infection can be accurately excluded by serology in young children born to HCV-infected mothers and to determine an appropriate schedule of antibody testing, most informative to clinical practice. Methods: Children born to HCV-infected mothers were followed in centres of the European Paediatric HCV Network. Turnbull survival analysis techniques were used to estimate the age at which HCV-uninfected children will lose maternally acquired HCVantibodies. Factors associated with age at antibody loss were assessed in logistic regression. Results: In 1104 children followed from birth and later confirmed to be HCV uninfected, an estimated 57% will have lost passively acquired HCVantibodies before 6 mo of age and an estimated 95% by 12 mo. Maternal HCV viraemia antenatally was associated with later, and maternal HIV-HCV coinfection with earlier loss of antibody. Actual antibody testing of uninfected children at 12 mo identified 82% of those tested to be anti-HCV negative. Conclusions: Serological confirmation of HCV uninfection remains necessary given the uncertainty in the specificity of virological tests. These results suggest that, in most children, HCV infection can be ruled out with serological testing at an earlier age than previously thought, and that nearly all children born to HCV-infected mothers will have lost passively acquired maternal antibodies by 1 y of age. Antibody loss was significantly later among children born to HCV viraemic mothers. The earlier loss of HCV antibodies in children born to HIV coinfected mothers may be due to HIV treatment. Aim: To identify the age at which HCV infection can be accurately excluded by serology in young children born to HCV-infected mothers and to determine an appropriate schedule of antibody testing, most informative to clinical practice. Methods: Children born to HCV-infected mothers were followed in the centers of the European Pediatric HCV Network. Turnbull survival analysis techniques were used to estimate the age at which HCV-uninfected children will lose their acquired HCV antibodies. Results: In 1104 children followed from birth and later confirmed to be HCV uninfected, an estimated 57% will have lost passively acquired HCV antibodies prior 6 mo of age and an estimated 95% by 12 months. Maternal HCV viraemia antenatally was associated with later, and maternal HIV-HCV Actual antibody testing of uninfected children at 12 mo identified 82% of those tested to be ant The results suggest that, in most of the children, HCV infection can be ruled out with serological testing at an earlier age than previously thought, and that nearly all children born to HCV-infected mothers will have lost passively acquired maternal antibodies by 1 y of age. Antibody loss was significantly later among children born to HCV viraemic mothers. The earlier loss of HCV antibodies in children born to HIV coinfected mothers may be due to HIV treatment.