The kinetics of inactivation of the simian rotavirus SA-11 by chlorine, chlorine dioxide and monochloramine were studied at pH 6, 8 and 10 using a purified preparation of single virions and a preparation of cell associated virions. With chlorine at pH 6, the rate of inactivation of the single virion was too fast to measure. Both virus preparations were inactivated more rapidly at pH 6 than pH 10. With chlorine dioxide, however, the opposite was true. Both virus preparations were inactivated more rapidly at pH 10 than at pH 6. The cell associated virus was more resistant to inactivation by the three disinfectants than the preparation of single virions. Chlorine and chlorine dioxide at pH 6 and pH 10 inactivated 99% of both virus preparations within 5 minutes, however, monochloramine at pH 8 required more than 6 hours for the same amount of inactivation.