Elastin is the functional protein component of the elastic fiber and it is related with some diseases such as atherosclerosis and pulmonary emphysema. The present study refers to the preparation of the ""' Tc labeled monoclonal anti-elastin antibody. The monoclonal antibody was incubated .with an excess of 2-iminothiolane. The radiochemical controls were carried out. Then, it was passed through a Sephadex G50 column. A peak corresponding to the radiolabeled antibody was obtained. The biodistribution pattern of the 99Tc-anti-elastin was studied in healthy male Swiss mice and the uptake of this labeled antibody was mainly in liver and kidneys. The results indicate that the labeled technique is simple, produces high labeling yields and has not been found to alter the immunochemical properties of the antibody.