An apparatus for forming air-laid absorbent cores, having a first and second mat-forming wheel, each of the mat-forming wheels having a series of moulds along its peripheral surface, air-laying means for supplying air-entrained fibrous material to the moulds, suction means maintaining the formed core elements in their moulds during a part of the path of the moulds on the respective mat-forming wheel and means for transferring a core element on the second mat-forming wheel onto a core element on the first mat-forming wheel while the latter core element still is maintained in its mould, at least the air-laying means associated with the second mat-forming wheel having means for supplying a mixture of air-entrained fibrous material and discrete particles. The two mat-forming wheels form a nip between each other that the second core element will abut the first core element before transfer.