Background Excessive exposure to noise places nurses at risk for safety events, near-misses, decreased job performance, and fatigue. Noise is particularly a concern in pediatric intensive care units, where highly skilled providers and vulnerable patients require a quiet environment to promote healing. Objective To measure noise levels and noise duration on specialty pediatric intensive care units to explore sources of noise and its effects on the health of registered nurses. Methods In a cross-sectional pilot study, levels and sources of noise in 3 different specialty pediatric intensive care units were assessed. Fifteen nurses were observed for 4-hour sessions during a 24-hour period. Sound pressure levels (noise) and heart rate were measured continuously, and stress ratings were recorded. Descriptive statistics were calculated for noise (level, source, location, and activity), heart rate, and stress. The Pearson correlation coefficient was calculated to analyze the relationship between heart rate and noise. Results Mean noise level was 71.9 (SD, 9.2) dBA. Mean heart rate was 85.2/min (SD, 15.8/min) and was significantly associated with noise, unit, within-unit location, nurse sources, and noise activities. The most frequent sources of noise were patients' rooms, care activities, and staff communications. Conclusions Noise levels in pediatric intensive care units exceed recommended thresholds and require immediate attention through effective interventions. Although noise was not associated with stress, a significant correlation with increased heart rate indicates that noise may be associated with adverse health outcomes. (American Journal of Critical Care. 2015;24:377-384) In 1974, the Office on Noise Abatement and Control within the US Environmental Protection Agency stated that noise could produce serious physical and psychological stress. 7 In order to protect patients and health care professionals, the agency recommended that sound pressure levels (SPLs) in hospitals should not exceed 45 dBA during the day and 35 dBA during the night. SPLs are measured in decibels, a logarithmic scale such that a 10-dB increase in sound level correlates with a doubling in perceived loudness. The decibel A scale is a frequencyweighted adjustment such that higher frequencies, which cause more hearing damage in humans, are weighted more heavily. The 45-dBA limit was identified to prevent workers from becoming annoyed or unable to carry out normal work duties. A limit of 70 dBA during a 24-hour period would prevent measurable noise-induced hearing loss. 8 The World Health Organization 9 stated that mean values for an 8-hour time-weighted average should not exceed 30 dBA, with peaks no greater than 40 dBA. In studies 1-6 on noise in ICUs, SPLs ranged from 35 dBA to more than 120 dBA, clearly exceeding recommendations.Elevated SPLs can be attributed to many sources, including monitor alarms, medical equipment, care activities, and staff conversations. [1][2][3]5,10 In a survey 11 of 100 critical care nurses, the nurses repor...