The objectives of this study were to compare the inactivation of Cryptosporidium parvum oocysts by ultraviolet (UV) disinfection and ozone as determined using a standard mouse assay and a cell culture method. Materials and methods discussed in this study included: production of oocysts and spike doses; UV and ozone disinfection of oocysts; animal infectivity; cell culture infectivity; and, quantitation of infection. Includes 14 references, table, figures.