The aim of this study was to investigate whether the non-invasive serum marker FibroTest-ActiTest (FT-AT) reliably predicts the histological stage of fibrosis and/or activity, and decreases the need for a liver biopsy. Twenty-five children with naive chronic hepatitis B were analyzed for haptoglobin, alpha 2-macroglobulin, apolipoprotein A1, bilirubin, gamma-glutamyl transferase, and alanine aminotransferase activity, and the FT-AT scores were computed. FT-AT scores were compared with histological data. FT predicted insignificant fibrosis in 14/23 (61%) patients at a cut-off level of 0.31. Nine patients (36%) had significant histological fibrosis, but none were predicted by FT. There was no correlation between FT scores and histological stage of fibrosis (r: -0.221, p = 0.228). All 4 patients with significant histological activity had corresponding significant activity in AT (100%). Fifteen out of the 19 patients (78.9%) with significant activity in AT had insignificant histological activity. At the cut-off level of 0.36, AT predicted insignificant activity in all 6 patients (100%). There was no correlation between AT scores and histological activity (r: 0.245, p = 0.237). According to histological data, 12 patients were candidates for treatment, but FT-AT did not predict 3 of them (25%). FT-AT does not appear ready for use in detecting either the stage of fibrosis or activity in children with chronic hepatitis B.