Abstract: Linear multivariable control systems disturbed by Gaussian stationary random sequences are investigated from the viewpoint of Shannon information theory. Relations between entropy rate, mutual information rate of system variables and the H∞ entropy of closed-loop transfer functions are derived using frequency domain calculation formulae of information rates. These relations interpret the minimum entropy H∞ control method and give time domain computing methods for reformation rates in terms of information theory. Our results introduce a new kind of instrument for further study of control systems in the framework of information theory.