Abstract The paper concerns a tuned mass dumper (TMD) design to improve the seismic response of an historical chimney located in an important Italian hydraulic plant. The chimney, built at the beginning of XX century, has about 50 m total height and its structure is completely in masonry. To understand the chimney’s dynamic response and evaluate the TMD characteristics (in terms of optimum mass, stiffness and damping values) to improve the seismic response, some numerical analysis are carried out by Finite Elements Models (FEM) represented two configurations, respectively: the “chimney” (Type A) and “chimney with TMD” (Type B). Both of the configurations are investigated by two different kind of FEMs: a FEM-Model 1 characterized by beam elements and a FEM-Model 2 characterized by solid elements. In the FEMs, observing the Italian Buildings Code, the local earthquake has been applied by a spectrum-compatible accelerograms by performing a “time history” analysis. The mechanical characteristics of the masonry (elastic modulus and compressive strength) implemented in the FEMs has been already determined by a set of experimental tests. Finally, optimizing the TMD characteristics, the seismic improvements in terms of base shear, compressive/tensile stresses and top displacements are shown.