Abstract: In the case of an air nozzle for pneumatic false-twist spinning having a yarn channel formed of at least two segments and having at least one compressed-air duct leading into the yarn channel, it is provided that for the formation of each compressed-air duct, a groove is worked into one of the segments that is open in the direction of the contact of the other segment and that is covered by the segment that follows. To accommodate selective changes in the compressed air duct configuration the segments are replaceable parts that are clamped by screw threaded nozzle housing parts.