The radiation resistance of a nickel magnetostrictive‐stack transducer in the presence of an identical in‐phase transducer at an air‐water surface was obtained. The transducers are resonant at 20 kc and their radiating surfaces are squares whose sides are 0.38 of the wavelength in water. Curves were obtained for the radiation resistance vs separation distance for electrical driving forces of the interacting transducer which were 1.0, 2.0, and 3.9 times the electrical driving force of the reference transducer. It was found that for a given driving force ratio, the radiation resistance with interaction oscillated about the value for the radiation resistance of the transducer with no interaction and that these oscillations decreased in amplitude as the separation distance was increased. Near 2λ, the interaction effect became negligible. Furthermore, it was found that the interaction increased with increasing electrical driving force of the interacting transducer. Qualitative agreement is found with treatments of the interaction radiation resistance of other physical situations, but an adequate analytical study of this case is needed.