We investigate cartelists’ merger behavior using the complete set of European Commission (EC) cartel decisions over a 28-year span and information on cartelists’ merger activities over the last 30 years.  We find that mergers occur frequently. But they cluster in a few particular industries and usually included only a minority of the cartel participants. We find that the EC’s leniency programs expedite merger. Voluntarily ceasing infringement does not affect merger timing; After caught in the act, co-conspirators merge at a substantially greater pace.  The results shed light on the design of merger policies and enforcement programs against cartels.