BACKGROUND & AIMS: Viral clearance involves immune cell cytolysis of infected cells. However, studies of hepatitis B virus (HBV) infection in chimpanzees have indicated that cytokines released by T cells can also promote viral clearance via non-cytolytic processes. We investigated the non-cytolytic mechanisms by which T cells eliminate HBV from infected hepatocytes. METHODS: We performed cytokine ELISA of serum samples from patients with acute and chronic hepatitis B. Liver biopsies were analyzed by in situ hybridization. HepG2-H1.3 cells, HBV-infected HepaRG cells, and primary human hepatocytes were incubated with interferon-γ (IFNγ) or tumor necrosis factor-α (TNFα), or co-cultured with T cells. We measured markers of HBV replication, including the covalently closed circular DNA (cccDNA). RESULT: Levels of IFNγ and TNFα were increased in serum samples from patients with acute vs chronic hepatitis B and controls. In human hepatocytes with stably replicating HBV, as well as in HBV-infected primary human hepatocytes or HepaRG cells, IFNγ and TNFα each induced deamination of cccDNA and interfered with its stability; their effects were additive. HBV-specific T cells, through secretion of IFNγ and TNFα, inhibited HBV replication and reduced cccDNA in infected cells without the direct contact required for cytolysis. Blocking IFNγ and TNFα after T-cell stimulation prevented the loss of cccDNA. Deprivation of cccDNA required activation of nuclear APOBEC3 deaminases by the cytokines. In liver biopsies from patients with acute hepatitis B, but not chronic hepatitis B or controls, hepatocytes expressed APOBEC3A and APOBEC3B. CONCLUSION: IFNγ and TNFα, produced by T cells, reduce levels of HBV cccDNA in hepatocytes by inducing deamination and subsequent cccDNA decay.