A biosimilar is a biological medicinal product that is highly similar to an authorized biological product in terms of quality, biological activity, safety and efficacy. SB5 was developed by Samsung Bioepis as a biosimilar referencing adalimumab, and was authorized by the European Commission (EC) in August 2017 (Imraldi®). Extensive characterization studies were performed to demonstrate functional similarity of SB5 to reference adalimumab (Humira®, AbbVie Inc. and AbbVie Deutschland GmbH & Co. KG). SB5 and Humira® showed highly similar soluble TNF-α binding and neutralizing activity, as well as transmembrane TNF-α binding activity and reverse signaling induced in the membrane TNF-α expressing cell line. Both products exhibited similar binding of the Fc gamma receptors and Fc-related effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). In addition, additional mechanisms of action induced by TNF-α, such as cytokine release and expression of adhesion molecules, were analyzed and shown to be similar between SB5 and Humira®. Taken together, our results demonstrate that SB5 and Humira® are highly similar in terms of their functional characteristics.