Enumeration of antigen-specific cells after vaccination is one of the prime immunological parameters determined when developing vaccines. Due to their exquisite sensitivity (limits of detection can be below 1/100,000 cells), ELISPOT assays are therefore an important tool in vaccine development programs. This is particularly the case for vaccines against diseases that require protective cell-mediated immunity, such as tuberculosis. This chapter describes ELISPOT assays detecting bovine IFN-γ.