The growth of amorphous silica nanowires by on-site feeding of silicon and oxygen is reported. The nanowires were grown on a nickel-coated oxidized silicon substrate without external silicon or oxygen sources. Transmission electron microscopy observation revealed that the nanowires, which have diameters of less than 50 nm and a length of several micrometers, were grown using a traditional vapor-liquid-solid mechanism. Blue photoluminescence was observed from these nanowires at room temperature. An approach to grow nanowires without external precursors may be useful when integrating nanowires into devices structures. This can benefit the fabrication of nanowire-based nanodevices.