Objective: To report outcomes from the first 2 years of the National Hand Hygiene Initiative (NHHI), a hand hygiene (HH) culture-change program implemented in all Australian hospitals to improve health care workers' HH compliance, increase use of alcohol-based hand rub and reduce the risk of health care-associated infections. Design and setting: The HH program was based on the World Health Organization 5 Moments for Hand Hygiene program, and included standardized educational materials and a regular audit system of HH compliance. The NHHI was implemented in January 2009. Main outcome measures: HH compliance and Staphylococcus aureus bacteraemia (SAB) incidence rates 2 years after NHHI implementation. Results: In late 2010, the overall national HH compliance rate in 521 hospitals was 68.3% (168 641/246 931 moments), but HH compliance before patient contact was 10%-15% lower than after patient contact. Among sites new to the 5 Moments audit tool, HH compliance improved from 43.6% (6431/14740) at baseline to 67.8% (106 851/157 708) (P < 0.001). HH compliance was highest among nursing staff (73.6%; 116 851/158 732) and worst among medical staff (52.3%; 17 897/34 224) after 2 years. National incidence rates of methicillinresistant SAB were stable for the 18 months before the NHHI (July 2007-2008; P = 0.366), but declined after implementation (2009-2010; P = 0.008). Annual national rates of hospital-onset SAB per 10 000 patient-days were 1.004 and 0.995 in 2009 and 2010, respectively, of which about 75% were due to methicillin-susceptible S. aureus. Conclusions: The NHHI was associated with widespread sustained improvements in HH compliance among Australian health care workers. Although specific linking of SAB rate changes to the NHHI was not possible, further declines in national SAB rates are expected.