Compositionally modulated GaP/GaAs1-xPx nanowires are grown by molecular beam epitaxy in the vapor liquid solid mode using Au as catalyst. By periodically supplying As, we achieve atomically flat and abrupt interfaces along the whole length of the nanowires. This is a step towards the realization of superlattices in nanowires. (C) 2010 Elsevier B.V. All rights reserved.