We studied the prevalence of diabetes mellitus in Singapore and compared it to the study conducted ten years previously. A rise in prevalence rates from 2.0% to 4.7% was demonstrated. Impaired glucose tolerance (IGT) was studied for the first time, and a prevalence rate of 0.9% was found. Findings on chronic complications of diabetes were also reported. A high frequency of coronary heart disease and hypertension were detected in both diabetic and IGT subjects. Obesity and hyperlipidaemia were identified as important risk factors. This study demonstrates the scope and impact of diabetes mellitus as a major healthcare problem in Singapore. Strategies directed at prevention and control of this disease needs to be implemented so as to check its rising trend.