An epitope can be defined as a molecular region on the surface of an antigen capable of eliciting an immune response. Epitope binning, also termed cross-competition assays, provides a method by which large antibody panels usually generated in antibody discovery programs are funneled down during the selection of lead molecules. Antibody binning can therefore be used in early-stage discovery of therapeutic mAbs to sort large panels into “bins” based on their ability to “block” one another’s binding to their specific antigen in a pairwise and combinatorial fashion. Selecting mAb clones with affinity to a wide range of epitopes increases the likelihood of choosing functionally relevant candidates. Octet® BLI technology is a biosensor-based automated, real-time, label-free analysis platform suitable for performing epitope binning analysis as a “setup-and-walk away” assay with both moderate-throughput and high-throughput capabilities. BLI platforms are based on the simple format of “dip and read.” In this format, sample handling relies on the movement of the disposable fiber optics-based tips containing the sensing surface into samples presented in a standard sample plate. The sampling method is advantageous over similar label-free techniques such as surface plasmon resonance (SPR) in that it allows for the specific analysis of target molecules within a crude sample such as cell culture supernatants, serum, or even plasma without the need to purify samples as sample clogging is not an issue. This chapter discusses the different epitope binning assay formats, the advantages and limitations of each, key aspects of assay development, and the advantages that the Octet® BLI platform offers over techniques such as surface plasmon resonance (SPR).