A sufficient condition that a 2-input 2-output system can be decoupled at sampling instants by a sampled-data state feedback is given, where it is assumed that the sampling period can be chosen arbitrarily. An important consequence obtained from this result is that a large class of systems which cannot be decoupled continuously can be decoupled at sampling instants. The result of simulation suggests that this scheme may be used as a means of quasi-decoupling.