Abstract: A synergistically effective composition with improved odor abatement properties has been devised which comprises a mixture of an enzyme, preferably a proteolytic enzyme, and a ferrous salt composition. The composition is particularly effective in reducing noxious odors emanating from waste materials by spreading the composition over the waste material. It also provides a process for the effective control of animal waste odors in commercial animal raising operations such as cattle feedlots, swine parlors, poultry operations, or the like, without affecting the usefulness of the waste material as fertilizer.