IN THIS PAPER, THE BEHAVIOR OF A TUNED MASS DAMPER (TMD), TO TORSIONALLY CONTROL A LINEAR STRUCTURE SUBJECTED TO SEISMIC EXCITATIONS, IS INVESTIGATED. THE DYNAMIC SYSTEM IS ANALYZED TAKING INTO ACCOUNT LATERAL-TORSIONAL COUPLING, SOIL?STRUCTURE INTERACTION, AND THE ROTATIONAL COMPONENTS OF THE FOUNDATION MOTION. THE SYSTEM MODEL CONSISTS OF AN ASYMMETRICAL STRUCTURE, FOUNDED ON A SOIL MODELED AS A HOMOGENEOUS SEMI-SPACE. A STATIONARY STOCHASTIC ANALYSIS IS PERFORMED IN THE TIME DOMAIN, AND A DOUBLE CLOUGH-PENZIEN FILTER OF BROAD FREQUENCY CONTENT IS USED TO DEFINE THE RANDOM PROCESS FOR THE X AND Y DIRECTIONS. THE TORSIONAL BALANCE CRITERION IS EMPLOYED FOR THE OPTIMIZATION OF THE TMD DESIGN PARAMETERS. THE INFLUENCE OF THE PLAN STATIC ECCENTRICITY OVER OPTIMUM TMD PARAMETERS BEHAVIOR IS ALSO ADDRESSED, TAKING INTO ACCOUNT THE FIXED BASE PERIOD, FLEXIBLE PERIOD, TORSIONAL FREQUENCY RATIO, AND SOIL TYPE. COMPLIANCE WITH THE TORSIONAL BALANCE IS VERIFIED. THE RESULTS SHOW THAT THE INCLUSION OF THE SOIL ROTATIONAL COMPONENT HAS A NOTORIOUS INFLUENCE ON THE OPTIMUM TMD PARAMETERS. MOREOVER, TORSIONALLY FLEXIBLE STRUCTURES FOUNDED ON SOFT AND MEDIUM SOIL SHOW SIGNIFICANT INFLUENCE ON THE TORSIONAL BALANCE. FINALLY, A TRANSITORY RESPONSE ANALYSIS IS CARRIED OUT FOR A 15-STORY MODEL, SUBJECTED TO AN ARTIFICIAL BIDIRECTIONAL EARTHQUAKE WITH A BROADBAND FREQUENCY CONTENT. THE MULTISTORY MODEL RESPONSE VALIDATES THE RESULTS DERIVED FROM THE STOCHASTIC ANALYSIS.