Background: Although numerous trials establish reliable profit of dietary sodium (Na+) restriction on blood pressure (BP) control in persons with hypertension; few studies tested the role of fractional sodium excretion “FENa" (a surrogate measure of dietary salt intake) as a predictor of hypertension resistance. Objective: study is aiming to correlate between urinary sodium excretion (UNA) and refractory hypertension (RfHTN). Methods: This study prospectively included 170 hypertensive patients from Zagazig university and police hospitals. Participants were categorized into two groups; group A (AG): 85 patients with controlled BP and group B (BG): 85 patients with uncontrolled BP. Ambulatory blood pressure (ABPM) measurements were used to assess BP and 24-h urine collection was used to estimate FENa level. Results: The present study showed statistically significant relationship between FENa and BP. FENa results came out with statistically significant differences between AG in compared to BG; median value of 1.07±0.31% in AG and median value of 1.25±0.65% within BG (P- value˂0.020). Subjects with 24UNA≥200mEq/day showed statistically significant difference regarding BP readings; mean SBP was 142.67±4.37mmHg in compared to 128.87±9.68mmHg in those with 24UNA