Abstract: Filter unit for connectors, comprising an electrically insulating substrate (2) with passages (3) for the contact elements of a connector, capacitors being disposed on both flat sides (4, 4') of the substrate (2) in the region of the passages (3), said capacitors made up of first electrodes, each formed by at least one layer (5, 5') of electrically conducting material extending over said sides (4, 4') of the substrate (2), and provided with correspondingly situated larger passages (6), second electrodes formed by spaced-apart electrode patches (9, 9') with passages (10) and at least one layer (7, 7') of dielectric material extending between said first and second electrodes. By connecting said second electrodes to the contact elements of a connector, and by connecting said first electrodes to the housing thereof, each contact element is capacitively decoupled.