A magnetostrictive transducer operating at 100 kHz using rare earth transition metal giant magnetostrictive material for nondestructive testing (NDT) applications was designed and fabricated. The giant magnetostrictive Tb0.3 Dy0.7 Fe2 material was chosen as the active element for the present purpose. From the impedance measurements, the resonant frequency of the transducer is found to be 100 kHz. The performance of the transducer was validated by carrying out NDT on a test concrete block with delaminated regions, using the ultrasonic through-transmission technique and the pitch-catch method. © 2008 American Institute of Physics.