Abstract: The invention relates to a method for the continuous reduction of the odor pollution caused by the waste water in sewers, comprising the following steps: a) determining the actual pollution of the waste water by means of a water sample of the waste water, b) calculating the quantity of odor-reducing agent required to reduce the odor pollution below a defined threshold value, using the degree of pollution, c) adding the defined quantity of odor-reducing agent to the waste water, d) continuously repeating steps a) to c). The aim of the invention is to devise a device and a method of the above type for reliably detecting odor pollution and for reducing it to a minimum using the odor-reducing agents. For this purpose, in step a) the pollution of the waste water is determined by determining the pollution of the water sample with odorous substances.