Background Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet enhances potassium intake and reduces sodium intake and blood pressure (BP), but the underlying metabolic pathways are unclear. Objective Among free-living populations, delineate metabolic signatures associated with the DASH diet adherence, 24-hr urinary sodium and potassium excretions and the potential metabolic pathways involved. Design 24-hr urinary metabolic profiling by proton nuclear magnetic resonance spectroscopy was used to characterize the metabolic signatures associated with the DASH dietary pattern score (DASH score) and 24-hr excretion of sodium and potassium among participants in the United States (n=2,164) and United Kingdom (n= 496) enrolled in the International Study of Macro- and Micronutrients and Blood Pressure (INTERMAP). Multiple linear regression and cross-tabulation analyses were used to investigate the DASH-BP relation and its modulation by sodium and potassium. Potential pathways associated with DASH adherence, sodium and potassium excretion, and BP were identified using mediation analyses and metabolic reaction networks. Results Adherence to DASH diet was associated with urinary potassium excretion (correlation coefficient, r = 0.42, P<0.0001). In multivariable regression analyses, a five-point higher DASH score (range 7 to 35) was associated with a lower systolic BP by 1.35 mmHg (95% confidence interval: -1.95, -0.80, P=1.2 × 10−5); control of the model for potassium but not sodium attenuated the DASH-BP relation. Two common metabolites (hippurate and citrate) mediated the potassium-BP and DASH-BP relationships, while five metabolites (succinate, alanine, S-methyl cysteine sulfoxide, 4-hydroxyhippurate, phenylacetylglutamine) were found specific to the DASH-BP relation. Conclusions Greater adherence to DASH diet is associated with lower BP and higher potassium intake across levels of sodium intake. The DASH diet recommends greater intake of fruits, vegetables, and other potassium rich foods that may replace sodium-rich processed foods and thereby influence BP through overlapping metabolic pathways. Possible DASH-specific pathways are speculated but confirmation requires further study.