The present study is intended to get to know thelevels of perimeter diurnal environmental noise of fourhospitals in the city of Lima. The measurement mode usedat each hospital was A-weighting, with an integration timeof five minutes per recording. It was measured in the FASTmode with calibrations made at the beginning and end ofthe measurement day. Statistical analysis consisted of themean comparison T test which was applied at all the hospi-tals considered in the study. At the four hospitals, at all thehours of measurement and both on working days and non-working days (Sunday), LAeq mean values are higher than83 dBA. On working days, two periods of maximum noisefrom 08:00 to 10:00 in the morning and from 17:00 to 19:00in the afternoon coincide with the start and end of workinghours. The perimeter diurnal environmental noise levelsdetermined at the vicinity of four hospitals show higherv...