Abstract Abstract The reduction of odor emanating from wasted swine manure is a very challenging environmental engineering problem. In an earlier work (Watkins et al., 1997), we showed the effect of ozone in reducing the odor and concentration of phenolic compounds in swine manure obtained from the pits under the slotted floors where the swine were housed. In this paper, we have expanded significantly upon the work of Watkins et al. by determining the effect of storage on the physical, chemical and biological characteristics of the swine manure slurry and whether the efficacy of ozonation is dependent upon storage time. Key Words: OzoneSwine Manure SlurriesOdor ReductionManure StoragePhenolic CompoundsPhenolp-Cresolp-EthylphenolSkatoleDisinfection