There are approximately 500,000 hospital acquired infections per year in Germany of which about 20-30% (100,000-150,000) could be prevented. Hospital acquired infections are associated with increased mortality and prolonged hospital stay. Based on approximately 4 additional days of hospital stay, nosocomial infections cause additional 2 million hospital days per year. In other words, 6 hospitals each with 1,000 beds would be caring solely for patients with nosocomial infections for 1 year in Germany. Experts agree that careful hand hygiene is the single most effective measure to prevent transmission of pathogens. The rate of nosocomial infections can be reduced by improved compliance of hand hygiene as demonstrated in the literature. The ''AKTION Saubere Hände'' (Clean Hands Campaign) is a national campaign by the National Reference Centre for the Surveillance of Nosocomial Infections, the Society for Quality Management in the Health System and the Action Alliance Patient Safety aimed at the sustained improvement of hand hygiene behaviour in German hospitals.