The quantum confined Stark effect has been investigated in InGaAs/InP quantum wires with widths down to 20 nm. The wires were fabricated by electron beam lithography and wet chemical etching using titanium as mask material. By metalorganic vapor phase epitaxy overgrowth high quantum efficiencies are achieved even for very narrow wire structures. We observe blue shifts in the luminescence peak energy up to 20 meV due to lateral quantization. After evaporating a semitransparent 50 angstrom thick gold Schottky contact we observe red shifts of the luminescence energy up to 25 meV due to the quantum confined Stark effect by applying a reverse bias voltage of typically 1 V.