The enzyme-linked immunospot (ELISPOT) assay is considered by many to be the gold standard for monitoring cellular immune responses. The method is highly sensitive, quantitative, easy to use, and amenable to high-throughput screening. Until recently, the ELISPOT assay has been limited to the characterization of only one effector molecule. Since the maintenance of both IFN- § and IL-2 by pathogen-specific T cells has been linked to a more favorable clinical outcome in human immunodeficiency virus (HIV) and Leishmania infections, an ELISPOT assay able to characterize both of these effector molecules would be helpful for monitoring immune responses to certain infectious agents. Nicole Bernard and colleagues from the McGill University Health Centre (mcgill/hostres/investigators/bernard/) present a protocol for Dual-Color ELISPOT Assay for the Simultaneous Detection of IL-2 and/or IFN- § Secreting T Cells in the January issue of Cold Spring Harbor Protocols (cshprotocols/TOCs/toc1_10.dtl). As interest in multifunctional T-cell monitoring in human diseases grows, this method is likely to be extensively used.