A new series of noise measurements in 10 points of the central zone in Rome, corresponding to residential areas with commercial activity, to parks, to hospitals, and to a subway, have been carried out. Investigation has been protracted during 24 hours and each measure has lasted 20 minutes. For the survey a mobile acoustic unity of the Environmental Hygiene Laboratory, Department of Sanitary Engineering, of Istituto Superiore di Sanità has been employed. The unity is fitted with instruments for statistical analysis of noise in connection with a minicomputer. The used program has allowed to calculate L1, L10, L50, L90, standard deviation, Leq, LNP, TNI. On the basis of such measurements Leq 24, Ldn, CNEL, have been calculated. Collected data have been compared with limits of stated rules and with noise levels measured in other seven Italian towns.