Abstract: A process is described for scrubbing of NO.sub.x and/or SO.sub.2 from waste gases as, e.g., flue gases, which employs a scrubbing agent comprising Fe(II) ions in nonaqueous solvents. The scrubbing agent can be regenerated after its loading simply by heating and/or reduction of pressure, after which the scrubbing agent can be reused. A slight reduction of the Fe(II) ion concentration occurring by oxidation can be balanced by simple means. The process makes it possible to scrub out NO or NO.sub.x alone or together with SO.sub.2. If SO.sub.2 alone is to be scrubbed out of a gas mixture, addition of Fe(II) salt can be eliminated.