The Dutch Public Health Act, which came into force on 1 December 2008, replaces the existing laws concerning the combating of infectious diseases. Important changes have been incorporated in the new Public Health Act in comparison with the previous law on infectious diseases. Diseases which are probably infectious in nature and caused by as yet unknown pathogens are now notifiable, laboratories also have a nominal duty of notification and the list of notifiable diseases has been extended with 10 new infectious diseases. The provisions in the law comply with the International Health Regulations of the World Health Organization. The Centre for Infectious Disease Control Netherlands at the Dutch National Institute for Public Health and the Environment (RIVM) has issued a booklet for all Dutch physicians and laboratories providing background information on notifiable diseases. This can be useful in daily practice for helping to decide whether a disorder or cluster of infections is notifiable.