The surface of poly(ethylene terephthalate) (PET) filament fabric was modified with Janus Particles (Jps) for water-repellency property. Jps were characterized with zeta potential measurement, fluorescent microscopy and X-ray photoelectron spectroscopy. The hydrophilic part of Jps bound to the activated PET filament surface and hydrophobic part of Janus faced the environment. The wetting and morphology of modified polyester surface were investigated with scanning electronic microscope and DAT 1100-FIBRO System and DAT 1129 Tilt Table. It was found that with the increase in the concentration of Jps, modified surface showed higher water contact angle and lower tilt angle. From the surface morphology it was also noticed that higher concentration of Jps gave raspberry-like aggregations on modified filament textile surface. Finally it was demonstrated that highest concentration (20 wt. %) of Jps was very efficient for the design of water-repellent textile fabric.