An estrogen derivative 1-(3, 17-alpha-estradiolyl propin-1-yl-3-(1,4,8,11-tetraazacyclotetradecyl)-propanate (ESTACPA) was synthesized. The product was purified by HPLC and characterized by NMR and IR spectroscopy. The synthesized compound was labeled with Tc-99m. The biodistribution studies were performed on female Albino Wistar rats. The rats were sacrificed and their organs were removed. The radioactivities of the organs were counted using a gamma-counter. The activity per gram tissue was calculated and time versus activity curves were generated. The Tc-99m-ESTACPA uptake by the uterus and ovary such as ER-rich tissues, were observed. The pancreas and stomach also showed a significant uptake.