A radiochemical technique has been developed for the determination of the release rates of short-lived fission gases from fuel specimens during irradiation. Fission-product gases with half-lives ranging from 1.7 sec to 3.9 min were employed in the development of the procedure. These were krypton-89, xenon-137, xenon-140, and xenon-141. The procedure involves the collection and analysis of the solid daughter products of these gases. The gases are swept through a long tube packed with stainless steel mesh, and the daughter products deposit on the mesh as they are formed. The mesh is analyzed radiochemically for the daughter species, strontium-89, cesium-137, barium-140, and cerium-141. From the results of these analyses, the release rates of the parent fission gases may be calculated with a knowledge of the transit time of the gases through the tran and the transport time from the point of release to the trap entrance.