The present invention relates to a method to inhibit bacteria from adhering to a submergible surface. The method contacts the submergible surface with an effective amount of at least one thiourea to inhibit bacterial adhesion to the submergible surface. The present invention also relates to a method for controlling biofouling of an aqueous system. This method adds an effective amount of at least one thiourea to inhibit bacteria from adhering to a submerged surface within the aqueous system. This method effectively controls biofouling without substantially killing the bacteria. The thiourea used in the method of the invention is a compound of formula (I). The present invention also relates to compositions containing thiourea compounds and useable in the above methods. The compositions comprise at least one thiourea in an amount effective to inhibit bacteria from adhering to submergible or submerged surfaces.