Abstract. We describe an effect of phase-locking catastrophe arising in an ensemble of a great number of oscillators interacting by means of their emitting waves. These waves can be either pulsatile, that is, soliton-like, or continuous stationary waves generated by the oscillators considered as resonators. Each one of these waves will introduce certain perturbations among the phases of the oscillators of the ensemble in such a way that it is possible to follow in time the distribution of these phases. In fact, we deduce the p.d.e's governing the evolution in time of this distribution, which displays a tendency of accumulating around certain of its values (phase-locking), and also of sudden increasing of the intensity of the physical effect (a "phase transition").