Abstract: 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a first distillation procedure from which acetone is recovered and a bottom product containing MIBK and impurities is withdrawn. This bottom product is fed to a second distillation column, where a vapour overhead product is withdrawn, condensed and fed to an overhead liquid-liquid separator. Part of an organic phase from the overhead liquid-liquid separator is fed to the second distillation column and part is fed to a third distillation column. A vapour overhead product is withdrawn from the third column which is condensed in the same said condensor. The condensed product is fed to the same said overhead liquid-liquid separator, and purified MIBK is withdrawn from the third distillation column. This invention also relates to an apparatus used in such a method.