A side channel pump, preferably a vacuum pump, includes a driven rotor (16) and a fixed stator (14). The rotor (16) and the stator (14) define a pump channel circulating in a peripheral direction. Blades are fixed onto the rotor, protruding into the cross-section of the pump channel. The pump channel also includes a blade-free side channel (44). The pump channel (22) containing the side channel (44) extends in a helical manner around the rotor (16). The pump channel is advantageously not limited to the length of a winding but can have the length of substantially any number of uninterrupted windings. As a result, a high suction performance and a high compression ratio in the pump can be obtained.