Solar ultraviolet radiation (UVR), through the formation of DNA photolesions, is the primary cause of most skin cancers. A better understanding of the mechanisms of UVR-induced DNA damage may help prevent skin cancer and this may be achieved using methods to quantify DNA damage. The immuno-slot blot (ISB) method is routinely used for detection and quantification of any heat- and alkali-stable DNA adducts for which a sufficiently specific monoclonal antibody is available. The main steps in ISB are fragmentation and denaturation of the DNA, immobilization of DNA to a nitrocellulose filter, incubation with primary antibody against a specific DNA adduct, incubation with an enzyme-linked secondary antibody and finally chemiluminescence detection and quantification of the DNA adducts.