We describe the trends in the incidence of methicillin-resistant Staphylococcus aureus nosocomial infection in intensive care units in Lyon hospitals from January 1, 2003, through December 31, 2006. The incidence rate decreased from 1.77 cases per 100 ICU patients in 2003 to 1.16 cases per 100 ICU patients in 2006, a reduction of 38.0% (P = .05).