Radiolabeling methods with the heavy halogens bromine, iodine and astatine are reviewed. The methods are evaluated on the basis of their underlying chemical principles and their usefulness for the no-carrier-added labeling of biologically-useful compounds. Special emphasis is placed on the stability, specific activity, and quality control of radiohalogenation products using the shortlived, neutron-deficient nuclides 7s ' 7 'Br, '"I, and 2 "At in view of their importance as radiopharmaceuticals.