The International Health Regulations require timely detection and response tooutbreaks. Many attempts to set up an outbreak early warning system in Pacificisland countries and territories (PICTs) have failed. Most were modelled onsystems from large countries; large amounts of data often overwhelmed smallpublic health teams. Many conditions required overseas laboratory confirmation,further reducing timeliness and completeness. To improve timeliness and reducethe data burden, simplified surveillance was proposed, with case definitions basedon clinical signs and symptoms without the need for laboratory confirmation orinformation on symptoms, location, sex and age. After trials in three PICTs, thissystem was implemented throughout the Pacific. Enthusiastic adoption by publichealth staff resulted in 20 of 22 PICTs reporting weekly to the World HealthOrganization within 12 months of starting to use the system. In the first year, thesystem has detected many infectious disease outbreaks and facilitated timelyimplementation of control measures. For several Pacific countries and territories,this is the first functional and timely infectious disease surveillance system. Whenoutbreak detection is the principal objective, simplification of surveillance shouldbe a priority in countries with a limited public health system capacity.