The alloying effect on K-beta/K-alpha intensity ratio in Cd1-xZnxS semi-conductor alloys and on structural, electrical and optical properties of these alloys were investigated. The sample was excited by gamma rays with energy 59.5 keV photons from an Am-241 radioisotope source. K X-rays emitted by the sample were counted with a Si(Li) detector. We found that the K-beta/K-alpha intensity ratio is changed by the alloying effect in Cd1-xZnxS semi-conductor alloys for different compositions x. We compared our results with the theoretical values. (c) 2004 Elsevier Ltd. All rights reserved.