In this paper the noise assessment for the "Jorge Chavez" International Airport of the city of Lima is presented. An algorithm as well as measuring set-up were specially prepared for this study and both will be discussed. The algorithm proved to be effective enough in discriminating both aircraft noise and background noise. The city of Lima is particularly noisy and therefore often aircraft noise is smeared with traffic noise. A map was prepared based on information supply by the airport administration; good agreement was found when the predicted levels were compared with the levels measured on ground. This study is the first complete study of this kind in Lima for aircraft noise.