M ANY recent investigations of cigarette smoke have been concerned with concentrations of polonium-210 and the radiation dose to the lungs of smokers who inhale it (1, 2). To ascertain if further insult to the lungs occurs, a study of the levels of other radionuclides, specifically lead-210 in cigarette smoke, was undertaken at the Northeastern Radiological Health Laboratory, Public Health Service. Limited data by Holtzman and Ilcewicz have indicated a transfer of lead-210 in the smoke (3), and stable lead in tobacco smoke has been reported also by Cogbill and Hobbs (4). Increased exposure of the lung to lead-210 may result because the nuclide has a longer effective half-life with subsequent daughter ingrowth. Calculations of the amount of lead-210 deposited in the lung, a critical organ, were based on the concentrations of lead-210 found in the smoke of various brands of cigarettes tested at this laboratory.