In modern communities, due to increasing density of residential housing near substations and transformers, there is an increased prevalence of local ordinances specifying sound levels at commercial and residential property lines. Therefore, it is appropriate that a good understanding of sources, measurement, and the mitigation options of sound energy radiated by transformers be developed for properly specifying sound levels in transformers. A good understanding of these principles can help us minimize the environmental impact of transformer noise on the neighboring communities.