Abstract: An ATM cell switch suitable for multicast switching comprises an input stage arranged to detect a multicast cell and to add to the cell header a switch header identifying the outputs to which copies are to be sent, a switch fabric arranged to identify multicast cells, to make identical copies thereof and to route the copies according to the switch header, and an output stage arranged to make further copies according to the data links which are to receive the multicast and to assign the appropriate VPI/VCI to the cell header of each copy according to data stored in said stage.