Abstract: The present invention provides a method for the removal of biofilms composed of microorganisms from submerged surfaces in an aqueous medium comprising contacting said biofilm with an aqueous stabilized chlorine dioxide and at least one nutrient source, wherein said nutrient source is provided in an amount effective to result in the generation of one or more acidic compounds by said biofilm, and the aqueous stabilized chlorine dioxide is provided in an amount sufficient, when activated by said one or more acidic compounds generated by said microorganisms, to kill a sufficient number of microorganisms in the biofilm to result in the biofilm's removal. Optionally a second biocide may be provided with or after the nutrient source to kill any microorganisms released from the biofilm during its removal and thereby inhibit the reformation of the biofilm.