A reversed-phase high-performance liquid chromatographic method is described that allows the simultaneous determination of up to eight amatoxins and phallotoxins. The method identifies both neutral toxins (alpha- and gamma-amanitin, phalloidin, phallisin and phalloin) and acidic toxins (beta-amanitin, phallacidin and phallisacin). Toxins were separated, identified and determined by gradient elution with 0.02 M aqueous ammonium acetate-acetonitrile and simultaneous monitoring of the absorbances at 214 and 295 nm. The assay was successfully applied to the analysis of the toxins in a crude extract of Amanita phalloides. The limit of detection for each toxin was 10 ng/ml of extraction medium. The assay was further validated by analysing the toxin content in Galerina marginata, a species containing only amatoxins. This relatively simple method should be suitable for the detection of amatoxins and phallotoxins in almost any species of mushrooms.