This invention relates to a method of producing purified methyl isobutyl ketone (MIBK) comprising subjecting a feed stream containing MIBK and impurities to a first distillation procedure from which acetone is recovered. The bottom product of the first distillation procedure is fed to a liquid-liquid separator and an organic phase from the said liquid-liquid separator is fed to the top region of a second distillation column to produce an overhead product. The said overhead product is condensed and fed to the said liquid-liquid separator. A bottom product containing MIBK is withdrawn from the second distillation column. This bottom product is fed to a third distillation column, high boiling impurities are withdrawn as a bottom product, and purified MIBK is also withdrawn. The invention also relates to an apparatus used in such a method.