Abstract Study of the brass configuration on wires from a number of cords from different sources shows that the brass on all of the wires is highly nonuniform in its distribution. It is not a “layer” as the word is generally understood. In some areas, the steel is almost bare; in some areas, brass coverage may be 0.1–0.2 µm thick; in still other areas there are “intrusions” of brass extending into the steel much more than a micrometer. It is believed that this brass configuration is typical of all steel wires which have been drawn after brass plating; hence, it is probably typical of all wires currently used in brass-plated steel tire cord. Consideration should be given to this erratic brass configuration in studies of adhesion of tire rubber to brass-plated steel tire cord. Perhaps the current model(s) should be modified to include the possible effect of the reservoirs of brass in the “intrusions” which exist in the steel.