Abstract The results of parenteral administration of the chelate trisodium calcium diethylenetriaminepentaacetate (DTPA) in five patients with iron storage disease are reported. DTPA given intravenously in doses of 2.5 to 4.0 Gm. resulted in iron excretion of up to 109 mg. per 24 hours in three patients with clinical hemochromatosis. Two control subjects showed no increase in urinary iron after the chelate was given. There was little, if any, clinical toxicity, and no significant effect on hemogram, urinalyses, blood urea nitrogen, or serum calcium. Prothrombin times were only slightly prolonged. Comparable iron excretion occurred after intravenous and intramuscular administration of DTPA. The amount of iron excreted in various subjects correlated best with the estimated iron stores. The hypothesis is advanced that parenterally administered DTPA is carried in the circulation to iron storage sites, the calcium in the chelate is exchanged for iron, and this complex continues in the circulation and is excreted in the urine. The increased efficiency of DTPA over EDTA is discussed. The clinical application of DTPA is not established but the results reported here suggest a possible role as a supplement to phlebotomy in the treatment of hemochromatosis, and as an alternative therapy for individuals with iron storage disease not suitable for phlebotomy.