This review on sterility immunology deals exclusively with immunological mechanisms hindering gamete junction. It does not elaborate the different immunological aspects of infertility after gamete junction. Thus spermatozoal seminal plasma and ovum antigens producing auto- or isoimmunization as immunological mechanisms hindering gamete junction in vitro and in vivo are discussed. Local immune response is compared to general immune response discerning between antibody production and cellular immunity. The commonly used diagnostic tools, the application of these test methods, the clinical therapeutical significance and the scientific objectives for further research in the area of reproductive immunology are outlined. It becomes evident that research in immunology of reproduction is performed with two targets: (1) diagnosis and treatment of the so-called 'immunological sterility', and (2) development of an immunological contraceptive.