Red blood cells values of 100 male heroin addicts, 100 male smokers and 100 normal men, all of like age, have been examined. Nearly all of the heroin addicts are heavy cigarette smokers. The GRC/mm3, Hb g%, Ht%, MCHC and MCV values did not show significant statistical differences between the three groups, except the MCV in the average appeared 2,8 mu3 higher in the smokers, than the normal non smokers. In heroin addicts there did not appear any variation related to abnormalities in liver function and dependency life time. The differences between the results of our studies and the literature are determined from a longer exposition to the damage caused from heroin and smoke.