Urinary zinc excretion is known to be elevated in subjects with sickle cell anemia. Sodium intake has been suggested to influence zinc excretion in normal subjects. In order to assess the effect of sodium on zinc excretion in subjects with sickle cell anemia, urinary zinc excretion was measured in thirteen children and adolescents with sickle cell anemia on both a high (140 mEq/day) and low (20 mEq/day) sodium intake. Urinary zinc excretion was elevated on both diets. The mean urinary zinc excretion on the high sodium diet (775 +/−238 micrograms/24 h) was significantly lower (P less than .005) than that on the low sodium diet (947 +/−344 micrograms/24 h). The zinc excretion did not correlate with calcium or magnesium excretion or aldosterone secretion rates or plasma renin activity. Although elevated, the urinary zinc excretion in patients with sickle cell anemia is still significantly lowered by increasing sodium intake.