A procedure is described for the determination of vitamin D2 in multi-vitamin tablets. The vitamin is released from the tablets by enzymic digestion, which is followed by solvent extraction and chromatography on a microparticulate silica column. Other fat-soluble vitamins do not interfere with the assay. The problem of defining and quantifying vitamin D2 in order to correlate results with biological potency is discussed. The procedure is suitable for stability studies.