The albedo factors (number, energy and dose) of the samples with various mean atomic number have been investigated at a scattering angle of 180 degrees. Fourteen different samples in the mean atomic number range 9.743 <= (Z) over bar <= 83.00 were obtained with bismuth and cellulose powders by using dilution technique. Thus, albedo factors have been investigated in a wide atomic number range. The samples were irritated by 662 keV gamma rays emitted from a Cs-132 radioactive source. The scattered gamma-rays were counted by an HPGe detector with active area of 200 mm(2). It has been observed that albedo factors decrease with increasing mean atomic number. Also, there is a high correlation between albedo factors and mean atomic numbers.