Abstract: A side-channel compressor includes a rotor rotatably supported in the housing of the compressor. The rotor includes a blade ring arranged at the outer circumference of a disk-shaped hub. A clearance space is provided between the housing and the rotor in the region where the rotor hub merges into the blade ring. To prevent the rotor from becoming blocked by dust, lint or fiber-like particles which may settle in the clearance space, at least one recess is formed in the rotor in the region where the hub merges into the blade ring. The recess extends over the entire effective length of the clearance space in the region where the hub merges into the blade ring and effectively expands the boundaries thereof.