Abstract
In the present paper it will be proved that the Lyapunov spectrum of an ergodic stationary homogenous linear differential system perturbed by Gaussian white noise dx = A(t)x dt + dW(t) (∈Rn) consists of only one element, namely the number λ = max(λn) where λn is the top exponent of the unperturbed system dx = A{t)xdt. The proof is based on Oseledec-Millionshikov's famous multiplicative ergodic theorem and the Floquet type representation of Wihstutz for the fundamental matrix of the ergodic stationary system dx = A{t)xdt.