A process is disclosed to produce an .alpha.-hydroxyiminophenylacetonitrile of the general formula [II]: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and Z are each as defined in the specification, characterized in that a crude nitrile containing a phenylacetonitrile of the general formula [I]: ##STR2## wherein R.sup.1, R.sup.2, R.sup.3 and Z are each as defined in the specification, is reacted with an alkyl nitrite in the presence of a base, after which the reaction mixture is extracted with water and then the separated aqueous layer is neutralized with an acid. According to this production process, the desired .alpha.-hydroxyiminophenylacetonitrile can be produced with high purity, in high yield and with ease by extracting the reaction mass with water and then neutralizing the separated aqueous layer with an acid.