A gamma-ray absorptometer system used to determine the density distribution in nuclear fuel rods was designed, assembled, and operated. The absorptometer emits a collimated beam from an irradiated thulium source that is transmitted through a rotating fuel rod. The photons in the attenuated beam are counted and the counts are recorded on teletype tape. The tape output for each fuel rod inspected is used to punch counting data into card form. Data cards from a series of fuel rods are positioned in a FORTRAN-language source program. A computer then calculates and prints such information as the standard deviation due to counting and to density variations; the maximum, minimum, and average counts; and the density equivalent of each count. Calculated density is then programmed into an x-y plotter and displayed versus rod length. The system was found to be sensitive to changes of <1% of theoretical density with 95% confidence of detecting changes >2% of theoretical. The design objectives of compactness, ease of operating, and amenability to use of modern computational techniques were achieved.