[en] A breast applicator has been designed and constructed to fit with Eldorado 'A' cobalt-60 beam unit. The applicator is described. The applicator has been found to be useful for alignment of the radiation beam for the management of the chest wall through tangential fields. The overlapping at the junction of supraclavicular and tangential fields is also found to be controlled. The radiation reactions in axilla and skin are within normal limits. The set up for the treatment of chest wall with the applicator is described. (M.G.B.)