OBJECTIVES: To verify the need of implementing noise reduction programs in the Neonatal Intensive Care Units (NICUs) of a university hospital, by measuring the ambient noise. METHODS: This cross-sectional descriptive analysis was approved by the IRB/UFES under No. 201 539. It was conducted at University Hospital NICU Cassiano Antonio de Moraes (HUCAM) of Federal University of Espírito Santo (UFES) located in the metropolitan area of Vitória/ES. The environment consists of 2 units (medium and high risk) with a maximum capacity of 6 beds each. During the measurements, the staff was asked to maintain its routine work, without deliberate noise reduction. The noise level was measured 3 times a day (08:30, 12:30, and 15:30) over 1 week. A decibel meter with data logger, model Instrutherm DEC-49, was used for measurements. RESULTS: The noise level varied randomly with a general average of 64.66 dB (A), which exceeds the maximum decibel (dB) level of 45 dB recommended by the American Academy of Pediatrics (AAP, 1997) and the desirable and acceptable levels of 35 dB and 45 dB, respectively, recommended by the Brazilian Association Technical Standards (ABNT, 1987). There was no difference between the noise levels in the 2 units. CONCLUSION: The level of noise in the NICUs studied is above the levels recommended by the AAP and ABNT, reflecting the need for immediate development and implementation of programs to reduce noise in this environment.