The half-value thicknesses, linear and mass attenuation coefficients of biological samples such as bone, muscle, fat and water have been measured at 140, 364 and 662 keV gamma-ray energies by using the ATOMLAB (TM)-930 medical spectrometer. The gamma-rays were obtained from Tc-99m, I-131 and Cs-137 gamma-ray point sources. Also theoretical calculations have been performed in order to obtain the half-value thicknesses and, mass and linear attenuation coefficients at photon energies 0.001 keV-20 MeV for bone, muscle and water samples. The calculated value and the experimental results of this work and the other results in literature are found to be in good agreement. (C) 2006 Elsevier Ltd. All rights reserved.