The objective of this study was to determine the inactivation kinetics of Cryptosporidium parvum (C. parvum) oocysts with chlorine dioxide as a function of pH. An additional goal was to consolidate all the data available in the literature for various types of reactors and water quality. Experiments were performed using 2.33-L amber glass bottles as batch reactors. The temperature of testing solutions described subsequently was maintained constant at 20 degrees C with a circulating water bath. Testing solutions were continuously stirred with the use of teflon coated stir bars and magnetic stir plates. Sample volumes were transferred from the reactor bottles to the vacuum filter apparatus through tubing with the aid of a peristaltic pump. The samples were collected, via vacuum filtration, on 47 mm Poretics Polucarbonate Track-Etched 1-um pore diameter filters. Other topics covered include: chlorine dioxide generation; oocyst preparation; disinfection procedures; inactivation assessment; and, CT calculation.