Abstract A reversed-phase ion-pairing liquid chromatographic method with UV detection at 214 nm is described for the determination of lincomycin A and lincomycin B in fermentation beers. The chromatographic system consists of a microparticulate octylsilica column and a mobile phase composed of 10 m M sodium dodecyl sulfte in ammonium phosphate-buffered aqueous acetonitrile (pH 6). Thermostating the column at 45°C improves the symmetry of the lincomycin peaks by eliminating fronting. The sample is diluted with phosphate buffer, centrifuged and the supernatant injected on the chromatographic column. The ion-pairing reagent causes lincomycin A and lincomycin B to be separated from each other and from all other substances present in raw fermentation beers. Precision of the assay for lincomycin A was 1.2% relative standard deviation. Recovery of spiked lincomycin A and lincomycin B from a fermentation beer sample was quantitative. A comparison of this high-performance liquid chromatographic (HPLC) method to a standard automated wet chemical method shows the HPLC method is more precise, specific and accurate, while being as simple to accomplish.