A method has been developed for the simultaneous analysis of biogenic amines, amino acids, and the ammonium ion in wine and beer. Aminoenones formed by the reaction of amino acids, biogenic amines, and the ammonium ion with the derivatization reagent diethyl ethoxymethylenemalonate are separated by HPLC. Reaction takes place in methanolic alkaline medium for 30 min in an ultrasonic bath. Further heating at 70 degrees C for 2 h produces complete degradation of excess derivatization reagent and byproducts. Comparison of the results of ammonium analysis and enzymatic analysis showed a good correlation (r = 0.953). The proposed analytical method has the following advantages: easy derivatization of wines and beers; quantification of 24 amino acids, nine biogenic amines, and the ammonium ion in a single injection; use of the photodiode array detector; complete degradation of excess derivatization reagent during sample preparation; and detection limits below 0.40 mg/L for amino acids and below 0.06 mg/L for biogenic amines.