The alkylation of hemoglobin is a proposed dose monitor for chemical carcinogens and mutagens. The binding of fifteen chemical carcinogens and mutagens to rat hemoglobin was determined. Direct acting carcinogens and indirect acting carcinogens including aromatic amines, halogenated hydrocarbons, nitrosamines, polycyclic aromatic hydrocarbons, aflatoxin B1 and benzene bound hemoglobin. The efficiency of carcinogen and mutagen hemoglobin was dose dependent and ranged from 0.007 to 2.3% of an oral dose. The binding of chemical carcinogens and mutagens to hemoglobin would appear to be generic so that it could be developed into a dose monitor for a large number of known carcinogens and mutagens.