The scientific underpinning for recommended levels of dietary sodium and potassium intake is of great importance to healthcare providers and policy decision-makers. Recent clinical trials and meta-analyses confirm the capacity of dietary sodium reduction and potassium supplementation to reduce blood pressure with no harmful effects on blood lipid levels in customary clinical settings. Blood pressure is thought to be a good surrogate for cardiovascular disease events and the most important preventable risk factor for mortality and disability-adjusted life years. Cohort analyses and related pooling studies that have been used to explore the relationship between dietary Na and CVD were all based on secondary analyses of datasets that were not designed for this purpose. Most are of insufficient quality to provide dependable information. The limited information available from clinical trial experience and cohort studies of higher quality suggests a reduction in dietary Na decreases CVD morbidity and mortality. Modeling studies suggest that a small reduction in dietary sodium would result in a sizable general population health benefit. Some countries have experienced a progressive decline in average dietary sodium consumption. However, there is no evidence of a corresponding trend in the United States, and almost the entire population is failing to meet dietary sodium and potassium guideline recommendations.