The invention relates to a method for automatically synchronizing a number of paper feeding channels of an inserting system involving the following steps: a) inspecting the sheets provided for output in one of the channels by comparing their group sequence number and their sheet sequence number with predetermined reference values; b) outputting the inspected sheets from this channel if their group sequence number and sheet sequence number correspond with the set reference values; c) inspecting the additional sheets provided for output in one or more additional channels if the group sequence number or the sheet sequence number of a previously inspected sheet does not correspond with the set reference values; d) outputting the sheets from the additional channels if their group sequence number and sheet sequence number correspond with the set reference values, and; e) identifying a group as a defective group and outputting the sheet with the smallest group sequence number and with the smallest sheet sequence number if none of the inspected sheets have the set reference group sequence number and reference sheet sequence number.