The extent of individual variation of the concentration of certain elements in human tissue has been studied. The data were obtained from emission spectrographic studies of human tissue which have been a joint research project between the Health Physics Division, Oak Ridge National Laboratory, and the Physics Department. University of Tennessee. Dr. ISABEL H. TIPTON of the University of Tennessee has directed the spectrographic work. There is strong evidence that within a homogeneous population group the fraction of the population exceeding the sample mean by a factor of three will not exceed 5 per cent of the population. This was true in nearly all cases where the sample size was sufficiently large to permit the estimation of 5 per cent of the population at the 95 per cent confidence level. Elements studied include Cd, Cu, Zn and Al in the kidney, liver and lung. These tests indicate that for such elements and under continuous exposure to radionuclides in the environment, only a small fraction of a homogeneous population group will receive a dose in excess of three times the mean dose for the group. This tends to validate the assumption of the Federal Radiation Council in its Report No. 1 concerning the distribution of the dose in such a group.