The Di@bet.es Study, conducted in Spain, is the first national survey to examine the prevalence of diabetes and impaired glucose regulation. The study used a population-based, cross-sectional, cluster sampling design, targeting the entire Spanish population. A total of 5,072 participants were included, with a participation rate of 55.8%. The overall prevalence of diabetes mellitus, adjusted for age and sex, was 13.8% (95% CI 12.8, 14.7%), with about half of these cases being undiagnosed (6.0%). The prevalence of isolated impaired fasting glucose (IFG) was 3.4%, isolated impaired glucose tolerance (IGT) was 9.2%, and combined IFG–IGT was 2.2%. The prevalence of diabetes and impaired glucose regulation increased significantly with age and was higher in men than in women. The study also found that obesity, abdominal obesity, hypertension, high triacylglycerol levels, low HDL-cholesterol, and a family history of diabetes were significantly associated with these conditions. The results provide valuable data for public health authorities to develop and implement clinical and preventive intervention programs to address the growing health and economic burden of diabetes in Spain.The Di@bet.es Study, conducted in Spain, is the first national survey to examine the prevalence of diabetes and impaired glucose regulation. The study used a population-based, cross-sectional, cluster sampling design, targeting the entire Spanish population. A total of 5,072 participants were included, with a participation rate of 55.8%. The overall prevalence of diabetes mellitus, adjusted for age and sex, was 13.8% (95% CI 12.8, 14.7%), with about half of these cases being undiagnosed (6.0%). The prevalence of isolated impaired fasting glucose (IFG) was 3.4%, isolated impaired glucose tolerance (IGT) was 9.2%, and combined IFG–IGT was 2.2%. The prevalence of diabetes and impaired glucose regulation increased significantly with age and was higher in men than in women. The study also found that obesity, abdominal obesity, hypertension, high triacylglycerol levels, low HDL-cholesterol, and a family history of diabetes were significantly associated with these conditions. The results provide valuable data for public health authorities to develop and implement clinical and preventive intervention programs to address the growing health and economic burden of diabetes in Spain.