RESUMEN
The objectives of the study were to assess sound pressure level (SPL) in two rooms of a Neonatal Intensive Care Unit (NICU) and to identify their sources. This quantitative-descriptive study was conducted in two rooms of a NICU of a University Hospital in São Paulo, Brazil. Three dosimeters were used to register SPL (total of 261 hours). A 48-hour register of noise sources was obtained. The results showed high SPL in both rooms. The greatest mean Leq were 71.0 dBA (room A) and 68.0 dBA (room B). Main noise sources in both units were: NICU hallway noise, traffic and conversation among professionals. The results indicate that SPLs in NICU rooms are higher than the levels recommended by regulatory agencies. A guideline was developed and an educational program was implemented as a means to reduce sound pressure levels.