The state of conservation of ancient lead objects of various dates from Italy was examined in relation to the purity of the metal in order to obtain information useful for the conservation of deteriorated antiquities. The objects were subjected to various types of physico-chemical investigation, using several techniques of analysis. It was concluded that the state of preservation depends, above all, on the purity of the metal and the nature of any impurities. Non-metallic impurities which are capable of forming water-soluble compounds are particularly dangerous.