The air drag on about 1 to 4 denier poly (ethylene terephthalate) monofilaments, which were spun in the high take-up velocities ranging from 6, 000m/min to 10, 000m/min, was investigated. The spinning stress was measured along the spinline below the oiling nozzle that was located at 20cm below the neck-like deformation point. The air drag coefficient (CD) on the monofilament can be expressed as a function of the radius Reynolds number (Rea): CD=0.26Rea-0.61. This obtained function agreed well with the functions obtained in other works which employed take-up velocities up to 6, 000m/min. This fact suggests that the air drag under the condition of this study is caused by the transitional flow from the laminar to turbulent flow.The air drag on the multifilaments that were bundled by the oiling nozzle was markedly reduced. The value of measured air drag agreed well with the calculated values based on the assumption that the bundled filaments were close-packed and behaved like a monofilament along the spinline.