One of the most widely accepted features of the dielectric breakdown, its irreversibility, is discussed. Experimental results are presented which demonstrate that the observed irreversibility is only due to the thermal damage caused by the local increase of the current density. It is demonstrated that these thermal effects can be externally limited so as to produce reversible dielectric breakdown events. Both constant-voltage stresses and ramped measurements confirm the idea that the breakdown is intrinsically a reversible electronic phenomenon. © 1993.