Abstract: Measurements of K-shell mass attenuation coefficients are reported for the first time in Arsenic oxide (As2O3). Experiments are performed using Arsenic Oxide extended range HPGe detector. To achieve measurements at many small and regular energy intervals, secondary X-ray emission technique using “Seventeen Scatters” is employed. The results are in agreement with the proposed theoretical estimates. No evidence could, however be gained in favor of microscopic theories such as RRS and EXAFS, insofar as there are no energy points within a range of 100eV on either side of the K-edge.