A method and system for treating cyanide-containing fluids, in particular cyanide-containing waste water, wherein cyanide-containing fluid is subject to a pretreatment in a pretreatment zone, in which at least one predetermined pH value and a predetermined temperature is set, wherein a base fluid is formed with the pretreatment. Base fluid is reacted at least with an oxidation means in at least one reaction reactor, whereby an oxidation reaction of the cyanide is initiated. Fluid from the reaction reactor is transferred as intermediate fluid into at least one process reactor, in which conditions exist in which the oxidation reaction of the cyanide initiated in the reaction reactor can take place, wherein a process fluid is formed. A continuous flow of fluid is maintained at least periodically, wherein the base fluid is transferred continuously from the pretreatment zone into the reaction reactor, intermediate fluid is transferred continuously from the reaction reactor into the process reactor, and process fluid is removed continuously from the process reactor.