The aims of this study were to obtain the most recent representative data for the prevalence of diabetes in adult populations in the World Health Organisation's South-East Asia and Western Pacific regions and to quantify the contribution of diabetes to the burden of mortality from cardiovascular diseases in these regions. Previous reports indicate that there are 83 million individuals with diabetes in the Asia-Pacific region, but since many of the country-specific estimates were not from nationally representative studies, this figure may not accurately reflect the current burden of diabetes. Information on the prevalence of diabetes was obtained by searching Medline and government health websites. Data were available from 12 countries representing 78% of the total population of the Asia-Pacific region. Six of 10 countries with complete data reported a prevalence of diabetes exceeding those estimates currently cited by the World Health Organization; three of which have also already exceeded the World Health Organization projections for 2030. In the 12 countries in the region with nationally representative data, the prevalence of diabetes ranged from 2.6% to 15.1%. Hazard ratios from the Asia Pacific Cohort Studies Collaboration were used to calculate population attributable fractions for diabetes for fatal cardiovascular diseases in the region. Population attributable fractions ranged from 2% to 12% for coronary heart disease, 1% to 6% for haemorrhagic stroke, and 2% to 11% for ischaemic stroke. Accurate estimates of the prevalence of diabetes are of great importance and standard methods are needed for periodic surveillance across the Asia-Pacific region and elsewhere.