The initial InAs growth on InP(1 0 0) during molecular beam epitaxy has been investigated. The as-grown islands were shaped like nanowires and formed dense arrays over the entire surface in the 3–6 monolayer InAs deposition range. The wires were oriented along the [View the MathML source 1 0] direction. Transmission electron microscopy images confirm that the wires are coherently grown on the substrates. Our results suggest that the coherent wire-shaped island formation may be a possible method to fabricate self-organized InAs nanowires.