The paper deals with the system \[ A(z)y_{n} = B(z)u_{n} + w_{n}, \] where \(u_{n}, y_{n}\) and \(w_{n}\) are the system input, output and disturbance, respectively; \[ \begin{aligned} A(z) & = 1 + a_{1}z + \ldots +a_{p}z^{p},\\ B(z) & = b_{1}z + \dots + b_{p}z^{p}\end{aligned} \] with \(z\) the backward shift operator i.e. \(zy_{n}= y_{n-1}.\) In particular, the paper deals with the above mentioned system in the case when the coefficient \[ \theta = [a_{1}, \ldots, a_{p}, b_{1}, \ldots, b_{p}] \] is unknown. The aim of the paper is to present a necessary and sufficient condition for the above mentioned system to be adaptively stabilizable. Moreover, in the paper, two methods of parametric modification for the adaptive pole-placement control are presented. In particular, one of them is nonrecursive and the other one is recursive based on the stochastic approximation technique.