Abstract. We study the exponential stabilization of the linearized Navier-Stokes equations around an unstable stationary solution, by means of a feedback boundary control, in dimension 2 or 3. The feedback law is determined by solving a Linear-Quadratic control problem. We do not assume that the normal component of the control is equal to zero. In that case the state equation, satisfied by the velocity field y, is decoupled into an evolution equation satisfied by P y, where P is the so-called Helmholtz projection operator, and a quasi-stationary elliptic equation satisfied by (I − P )y. Using this decomposition we show that the feedback law can be expressed only in function of P y. In the two dimensional case we show that the linear feedback law provides a local exponential stabilization of the Navier-Stokes equations.Key words. Dirichlet control, feedback control, stabilization, Navier-Stokes equations, Oseen equations, Riccati equation AMS subject classifications. 93B52, 93C20, 93D15, 35Q30, 76D55, 76D05, 76D071. Setting of the problem. Let Ω be a bounded and connected domain in R 2 or R 3 with a regular boundary Γ, ν > 0, and consider a couple (w, χ) -a velocity field and a pressure -solution to the stationary Navier-Stokes equations in Ω:We assume that w is regular and is an unstable solution of the instationary Navier-Stokes equations. The purpose of this paper is to determine a Dirichlet boundary control u, in feedback form, localized in a part of the boundary Γ, so that the corresponding controlled system:be stable for initial values y 0 small enough in an appropriate space X(Ω). In this setting, Q ∞ = Ω×(0, ∞),in Ω, y · n = 0 on Γ , and the operator M is a restriction operator precisely defined in section 2. If we set (z, q) = (w + y, χ + p) and if u = 0, we see that (z, q) is the solution to the Navier-Stokes equationsThus y 0 is a perturbation of the stationary solution w.To study the local feedback stabilization of system (1.2), we first study the feedback stabilization of the corresponding linearized system(1.3)To stabilize this system we can look for a control u belonging either to L 2 (0, ∞; V 0 (Γ)) or to L 2 (0, ∞; V 0 n (Γ)), where V 0 (Γ) = y ∈ L 2 (Γ) | y · n, 1 H −1/2 (Γ),H 1/2 (Γ) = 0 and V 0 n (Γ) = y ∈ L 2 (Γ) | y · n = 0 on Γ .