We synthesized, at room temperature, noble multi-metallic (Pt-Pd-Rh, and Pt-Pd-Au-Rh) ultrathin nanowires using a one-step phase-transfer approach. These multi-metallic nanowires then were characterized by x-ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy. The diameters of the nanowires range from 2 to 2.7 nm, and their lengths from tens to hundreds of nanometers. The multi-metallic nanowires were determined to be face-centered cubic structures. The compositions of the nanowires are quite uniform from wire to wire. Our results verify that the phase-transfer is a robust method for synthesizing various multi-metallic nanowires, which are expected to have potential applications in catalysis, magnetic storage, and bio-sensors.