Biological drugs (tumor necrosis factor inhibitors, rituximab, tocilizumab, abatacept, and tofacitinib) are important treatment alternatives in rheumatology, particularly for resistant patients. However, they may cause hepatitis B virus (HBV) and hepatitis C virus (HCV) reactivation; for instance, HBV reactivation may occur in a patient who is an inactive hepatitis B surface antigen (HBsAg) carrier or who has resolved HBV infection. Therefore, the screening of patients before biological treatment and the application of a prophylactic treatment, particularly with respect to latent HBV infections, are recommended when necessary. This guideline covers pre-treatment screening and follow-up recommendations, if required, with respect to viral hepatitides in rheumatology patients who are planned to be given biological drugs. Although this guideline is prepared for biological disease-modifying antirheumatic drugs (DMARDs), it is recommended to be used also for target-oriented DMARDS and medium-high dose corticosteroids (>7.5 mg prednisolone/day equivalent). It should be considered that the reactivation risk is higher when more than one immunosuppressive drug is used.