BACKGROUND: An association between use of hand hygiene products and health care-associated infection rates was investigated in a large Norwegian university hospital. METHODS: We conducted an ecologic study by combining data from purchasing and admission systems with data from 32 point prevalence surveys (27,248 patients) in 1998-2005. Data on purchase of hand disinfectants and soap, and patient-days, were collected for 20 bed wards similar to those of the prevalence surveys. RESULTS: The prevalence of infections was 7.1%. We found no significant decline in overall infections (P = .19), but use of hand hygiene products significantly increased from 28.5 L per 1000 patients-days in 1998 to 43.3 L per 1000 patient-days in 2005 (P 9% at study start in 1998 (P