Mouse models of immunology are frequently used to study host responses to poxviruses or poxvirus-based recombinant vaccines. In this context, the magnitude of CD8(+) T cell responses is often of interest. Methods to evaluate CD8(+) T cell responses extend from those that rely on indirect measurement of effector function only, such as cytotoxicity assays, to those that only measure antiviral CD8(+) T cell numbers and not function, like peptide MHC tetramers. In this chapter, five methods are provided that cover this range: DimerX staining (a variant of peptide-MHC tetramers), intracellular cytokine staining for interferon-γ, CD62L/Granzyme B staining, and in vitro and ex vivo cytotoxicity assays. We also include tables of vaccinia virus peptide epitopes for use in most of these assays.