The elastic contact of rough surfaces has been studied by Greenwood and Williamson [Proc. R. Sec. London, Ser A 295, 300 (1966)] for Hertzian contacts and by Fuller and Tabor [Proc. R. Sec. London, Set: A 345, 327 (1975)] for Johnson-Kendall-Roberts contacts. The theory for Deryagin-Muller-Toporov contacts is proposed here and compared with previous results. An extra load due to adhesion forces acting around the contacts appears, which can account for the friction under negative load and the increase in the apparent friction coefficient on clean surfaces.