High salt intake significantly increases the blood pressure of Sprague Dawley and Dahl salt-sensitive rats. Sprague Dawley (SD) and Dahl salt-sensitive (S) and salt-resistant (R) rats were fed low (0.3%, LS) or high (8%, HS) salt diets for three weeks. Indirect blood pressure (systolic) was measured before initiation of the diets and weekly by tail cuff plethysmography. Values are means ± SEM, n = 6. ***P < 0.001, baseline vs. week 3 of all groups except R-LS (**P = 0.01). ***P < 0.001, S-HS vs. S-LS at week 3. *P < 0.05, SD-HS vs. SD-LS at week 3.