A method for treating cyanide-containing liquids, more particularly cyanide-containing wastewater, wherein a) cyanide-containing liquid is subjected in a pretreatment zone to a pretreatment wherein at least a specified pH between 3 and 12 and a specified temperature are established, the pretreatment forming a base liquid; b) base liquid having a temperature between 40°C and 60°C enters at least one reaction reactor and is admixed in that reaction reactor at least with an oxidizing agent in the form of hydrogen peroxide, thereby initiating an oxidation reaction of the cyanides, c) liquid from the reaction reactor is transferred as intermediate liquid into at least one process reactor, in which conditions prevail under which the cyanide oxidation reaction initiated in the reaction reactor is able to proceed, forming a process liquid; d) at least periodically a continuous liquid stream is maintained, wherein da) base liquid is transferred continuously from the pretreatment zone into the reaction reactor; db) intermediate liquid is transferred continuously from the reaction reactor into the process reactor; and dc) process liquid is withdrawn continuously from the process reactor; characterized in that e) base liquid and/or intermediate liquid and/or process liquid is returned into the pretreatment zone by means of an analytical circuit facility (88, 90, 92, 94, 96), the analytical circuit facility ascertaining the cyanide concentration in the respective liquid (66, 72, 88); and f) process liquid is returned into the pretreatment zone; and/or g) process liquid on withdrawal is transferred at least partly into a storage vessel, and liquid from the storage vessel is returned into the pretreatment zone. a) cyanide-containing liquid is subjected in a pretreatment zone to a pretreatment wherein at least a specified pH between 3 and 12 and a specified temperature are established, the pretreatment forming a base liquid; b) base liquid having a temperature between 40°C and 60°C enters at least one reaction reactor and is admixed in that reaction reactor at least with an oxidizing agent in the form of hydrogen peroxide, thereby initiating an oxidation reaction of the cyanides, c) liquid from the reaction reactor is transferred as intermediate liquid into at least one process reactor, in which conditions prevail under which the cyanide oxidation reaction initiated in the reaction reactor is able to proceed, forming a process liquid; d) at least periodically a continuous liquid stream is maintained, wherein da) base liquid is transferred continuously from the pretreatment zone into the reaction reactor; db) intermediate liquid is transferred continuously from the reaction reactor into the process reactor; and dc) process liquid is withdrawn continuously from the process reactor; characterized in that da) base liquid is transferred continuously from the pretreatment zone into the reaction reactor; db) intermediate liquid is transferred continuously from the reaction reactor into the process reactor; and dc) process liquid is withdrawn continuously from the process reactor; e) base liquid and/or intermediate liquid and/or process liquid is returned into the pretreatment zone by means of an analytical circuit facility (88, 90, 92, 94, 96), the analytical circuit facility ascertaining the cyanide concentration in the respective liquid (66, 72, 88); and f) process liquid is returned into the pretreatment zone; and/or g) process liquid on withdrawal is transferred at least partly into a storage vessel, and liquid from the storage vessel is returned into the pretreatment zone.