Ten radiopharmaceuticals in frequent clinical use were examined for their radiochemical purity. Thin-layer chromatography, paper chromatography and electrophoresis were used. The activity of the separated components was measured in a gamma sample changer. The assumed chemical identity of the radiochemical impurities was evaluated by comparing the results with data described in the literature. For all radiopharmaceuticals tested, the radiochemical purity was found to be not lower than the value claimed by the manufacturer and to be in accordance with the requirements of the European Pharmacopoeia as far as those pharmaceuticals are listed therein.