Collating apparatus for stacking generally flat articles comprises a chute on opposite sides of which are two pairs of conveyor bands carrying supports for the articles. The conveyor bands are driven as two diagonally opposite pairs so that the stack builds on the supports of one pair of bands while a preceding stack built on the supports of the other pair of bands is discharged from the chute. The supports carried by the bands also comprise members which act on the completed stack to compress it before it is discharged.