Lymphoscintigraphy is an established means to determine the lymphatic drainage patterns from malignant tissues and edematous extremities. Unfortunately, there are no commercially available dedicated radiopharmaceuticals labeled for use in lymphoscintigraphy studies. The authors report a simple way to extemporaneously compound pharmaceutical-grade Tc-99m dextran 70 to meet this need. Pharmaceutical-quality Tc-99m dextran 70 injection is prepared by a simple rapid method from drug intermediates that are marketed as parenteral drug products. The radiolabeling process yields a product of high radiochemical purity, with good in vitro and in vivo stability. The authors illustrate the use of this product in a patient with melanoma to show the lymphatic drainage pattern before surgery. The method described permits rapid compounding of Tc-99m dextran 70 injection from drug components that are intended for parenteral administration. Tc-99m dextran 70 provides the option of performing lymphoscintigraphy in any clinical nuclear medicine setting.