This paper examines the effects of using aluminum electromagnetic shields in a distribution transformer. The goal of placing electromagnetic shields in the distribution transformer tank walls is to reduce the stray losses. A 500 kVA shell-type transformer is used. The overall results presented in this research work indicate that stray losses can be considerably reduced when electromagnetic shielding is applied to the transformer tank. In the experiment, the walls of the steel tank of the transformer were lined with aluminum foil. A section of this paper is devoted to the characterization of stray losses against the transformer rating (kVA) and the stray losses over load losses against the transformer rating (kVA). The experimental data presented in this work, will be helpful for a practicing engineer in the transformer industry.