The problem of pole assignment by state feedback in linear, non-square system is discussed. The conceptof regularizability is generalized to the concept of weak regularizability, which is then used in solving the problem. The conditions for the weakly regularizability are given. Then, if the system is weakly regularizable, the pole assignment is a well defined problem. Necessary and sufficient conditions for the pole assignment problem concerning the maximal number of poles,that can be assigned at our will, are given.More general conditions are established, but they are not sufficient in general.