Abstract: A method of recovering krypton and xenon nuclides from waste gases of nuclear power plants which comprises conveying a stream of waste gas at atmospheric pressure through a bed of activated carbon in an adsorber until the nuclides begin to issue at the outlet of the adsorber. The bed is thereupon regenerated by reducing the pressure therein to 10-300 torr to obtain a desorption gas which can be admixed to waste gas by rinsing the bed with a fluid (preferably an inert gas) at a pressure of 10-400 torr to obtain a stream of product gas which contains a high concentration of nuclides, and by thereupon raising the pressure in the adsorber with an inert gas back to atmospheric pressure.