Background and Aim: In chronic hepatitis B infection, antiviral therapy significantly reduces the incidence of complications. This study aimed to present real-life 12-month effectiveness and safety data for TAF. Materials and Methods: This Pythagoras Retrospective Cohort Study in cluded patients from 14 centers in Turkiye. The study presents 12-month results of 480 patients treated with TAF as initial therapy or after switching from another antiviral drug. Results: The study shows treatment of about 78.1% patients with at least one antiviral agent (90.6% tenofovir disoproxil [TDF]). The rate of unde tectable HBV DNA increased in both treatment-experienced and naive pa tients. In TDF-experienced patients, the rate of alanine transaminase (ALT) normalization increased slightly (1.6%) within 12 months, but the change was not statistically significant (p=0.766). Younger age, low albumin, and high body mass index and cholesterol were identified as risk factors for abnormal ALT after 12 months, but no linear relationship was detected. In TDF-experienced patients, renal and bone function indicators showed sig nificant improvement three months after the transition to TAF and remained stable for 12 months. Conclusion: Real-life data demonstrated effective virological and bio chemical responses with TAF therapy. After switching to TAF treat ment, gains in kidney and bone functions were achieved in the early period.