Abstract: A process is provided for isolating vanillin from alkaline aqueous solutions containing unwanted, chemically-related phenolic impurities, such as orthovanillin, acetovanillone, para-hydroxybenzaldehyde, syringaldehyde and the like, wherein the alkaline aqueous solution is subjected to an extractive process including as a step, extractive bisulfitation. The step of extractive bisulfitation involves the formation of an alkali-metal bisulfite complex of vanillin in the presence of a substantially water-insoluble organic solvent, such as a water-insoluble alkanol, e.g., normal-butyl alcohol.