Purpose The aim of the study was to analyze the exposure effects of different types of noise measures carried out at preschools. The project was carried out as an intervention study. Methods The investigation included 89 employees at 17 preschools in the northern part of Sweden. Individual noise recordings and recordings in dining rooms and play halls were made at two departments in each preschool. The adverse effects on the employees were analyzed with validated questionnaires and saliva cortisol samples. Evaluations were made before and 1 year after the first measurement. Between the two measurements, measures were taken to improve the sound environments at the preschools. Results The effects of the measures varied a lot, with respect to both the sound environments and health. Regarding acoustical measures, significant changes were seen for some of the variables analyzed. For most of the tested effects, the changes, however, were very small and non-significant. The effects of organizational measures on the objective and subjective noise values were in overall less pronounced. Conclusion Acoustical measures improved the subjectively rated sound environment more than organizational measures. This may be due to the high work effort needed to implement organizational measures. Even though the sound level was not lower, the personnel experienced improvements of the sound environment. (author abstract)