Objectives: Sodium plays a major role in the regulation of blood pressure. Both blood pressure (BP) and sodium retention in the kidney have both been linked to creatine kinase (CK), the enzyme that rapidly regenerates ATP for ATPases involved in pressor responses and salt retention: ADP + P∼creatine < = > ATP + Creatine.Therefore, we assessed BP and urinary sodium excretion (U_Na+) after a high sodium diet in in African and European men with high and low CK Methods: Sixty healthy men (29 European and 31 African ancestry) 18–50 y, normotensive or with uncomplicated untreated primary hypertension, were assigned to low sodium (LS) intake (<50 mmol/d) during 7 days, followed by 3 days of high sodium (HS) intake (>200 mmol/d). On day 7 (LS) and day 10 (HS), participants collected 24-h urine for U_Na+; and body weight, resting sitting blood pressure, 24 h BP, pulse wave velocity (PWV), central BP were measured (Arteriograph) Results: Table 1. depicts baseline parameters. Mean 24-h urinary sodium excretion during LS was 31.5 (3.5) and HS was 320.0 (21.1) mmol/24-h (p < 0.001), indicating adequate diet compliance. Sitting systolic and diastolic BP increased significantly during high salt as expected, with significantly higher 24 h BP and central systolic BP in African ethnicity (Table 2). PWV did not significantly differ between ethnic groups 6.4 (0.1) vs 6.6 (0.2). Sodium excretion (mmol/24-h) after high sodium was 260.4 (28.3) in the high CK tertile versus 415.2 (26.3) mmol/24-h in the low CK tertile (p < 0.001), with a decrease in urinary sodium excretion of 98.4 mmol/24-h for each increase in log CK, adjusted for age and African ancestry (Figure). Conclusion: Men of African ancestry have higher peripheral and central systolic but not diastolic blood pressures and lower sodium and potassium excretion after a high salt load.