OBJECTIVE: To determine the prevalence of prediabetes and diabetes among rural and urban Malaysians. RESEARCH DESIGN AND METHODS: This cross-sectional survey was conducted among 3,879 Malaysian adults (1,335 men and 2,544 women). All subjects underwent the 75-g oral glucose tolerance test (OGTT). RESULTS: The overall prevalence of prediabetes was 22.1% (30.2% in men and 69.8% in women). Isolated impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were found in 3.4 and 16.1% of the study population, respectively, whereas 2.6% of the subjects had both IFG and IGT. Based on an OGTT, the prevalence of newly diagnosed type 2 diabetes was 12.6% (31.0% in men and 69.0% in women). The prediabetic subjects also had an increased prevalence of cardiovascular disease risk factors. CONCLUSIONS: The large proportion of undiagnosed cases of prediabetes and diabetes reflects the lack of public awareness of the disease.