Abstract: The present disclosure pertains to an Fc variant having an improved half-life due to pH-dependent association and dissociation from FcRn. The Fc variant has a maximized blood half-life and exhibits a pH-sensitive FcRn association and dissociation ability superior to those of conventional blood half-life-improved Fc variants. Thus, the Fc variant can bind to numerous peptide drug therapeutics having a low half-life and retention time in the body, thereby enabling the peptide drug therapeutics to have an increased blood half-life and exhibit long-term drug efficacy. Accordingly, the dosage and frequency of administration of antibodies and biopharmaceuticals can be drastically reduced, and there is an effect of reducing the cost of new drug development and greatly improving the possibility of developing new drugs.