The binding of chemical carcinogens to DNA is well established as the initiating step in the process of carcinogenesis. While early studies in animals or cells in culture took advantage of radiolabeled model carcinogens such as benzo(a)pyrene, interest in measuring DNA damage levels in humans necessitated the development of alternative methods. Among these, immunologic methods using polyclonal or monoclonal antibodies to carcinogen-DNA adducts have proven extremely useful in monitoring human exposure as well as being applicable to animal and cell culture studies. Here we describe the use of antibodies for immunohistochemical analysis of tissue sections, biopsies, or intact cells and for quantitation of carcinogen binding in DNA isolated from blood and tissues by enzyme-linked immunosorbent assays.