Applications of the polymerase chain reaction have revolutionized the field of immunogenetics, particularly in studies of human leukocyte antigen class II polymorphism, and more recently in the analysis of T-cell receptor usage. However, the enormous diversity and variability of the T-cell receptor complex have made the amplification of the complete repertoire difficult. Several methods have been devised to address this problem. Each system is described with recent examples of its use and an assessment of its advantages and disadvantages. The use of quantitative polymerase chain reaction in T-cell receptor analysis is also discussed. The elucidation of the T-cell repertoire involved in a pathogenic process can have therapeutic implications, given the success of reversing experimental autoimmune disorders by directing specific forms of immunotherapy against V region gene products.