This research reports on the design and experimental verification of a tuned inertial mass electromagnetic trans- ducer (TIMET) for energy harvesting from vibrating large structures and structural vibration control devices. The TIMET consists of a permanent-magnetic synchronous motor (PMSM), a rotational mass, and a tuning spring. The PMSM and the rotational mass are connected to a ball screw mechanism so that the rotation of the PMSM is synchronized with the rotational mass. And the tuning spring interfaced to the shaft of the ball screw mechanism is connected to the vibrating structure. Thus, through this ball screw mechanism, transla- tional vibration motion of the structure is converted to rotational behavior and mechanical energy is absorbed as electrical energy by the PMSM. Moreover, the amplified equivalent inertial mass eﬀect is obtained by rotating relatively small physical masses. Therefore, when the stiﬀness of the tuning spring is determined so that the inertial mass resonates with the natural frequency of the vibratory structure, the PMSM rotates more eﬀectively. As a result, the generated energy by the PMSM can be increased. The authors design a prototype of the TIMET and carry out experiments using sine and sine seep waves to show the eﬀectiveness of the tuned inertial mass mechanism. Also, an analytical model of the proposed device is developed using a curve fitting technique to simulate the behavior of the TIMET.