BACKGROUND: Hand hygiene promotion for patient safety is a challenge worldwide, and local data are critical to tailor strategies to the setting. METHODS: This is a cross-sectional study of nurses and physicians providing direct patient care in four hospitals in Hong Kong using an anonymous questionnaire survey. Cognitive factors related to hand hygiene and the perception of effective interventions promoting hand hygiene were assessed. RESULTS: The overall response rate was 59.3%. Among respondents, 70% of the nurses and 49% of the physicians perceived that over 15% of patients would suffer from healthcare-associated infections. A total of 79% of the nurses and 68% of the physicians believed that more than 5% of patients would die as a result of healthcare-associated infection. A total of 60% of the nurses and 46% of the physicians acknowledged that over 75% of healthcare-associated infections could be prevented by optimal hand hygiene practices, although 36% of the nurses and 23% of the physicians claimed that six to ten hand cleansing times per hour would be necessary. Bivariate analysis showed significant differences between professionals in self-reported performance. A multivariate regression model revealed that perceived behavioral control and subjective norms were the most important factors associated with the nurses and physicians' self-reported hand hygiene performance. However when gender was taken into account among professionals, subjective norms was the only consistent one. CONCLUSION: These results could be used as a tool to create goal-specific strategies for motivating hand hygiene amongst nurses and physicians in Hong Kong, with appropriate promotional interventions delivered to the different professional groups and specialties.