A process for preparing xylylenediamine, comprising the steps of ammoxidizing xylene to phthalonitrile and hydrogenating the phthalonitrile, which comprises contacting the vaporous product of the ammoxidation stage directly with a liquid organic solvent or with molten phthalonitrile (quench),partly or fully removing components having a boiling point lower than phthalonitrile (low boilers) from the resulting quench solution or suspension or phthalonitrile melt and, after the low boiler removal and before the hydrogenation, removing products having a boiling point higher than phthalonitrile (high boilers).