A new teicoplanin-like antibiotic was discovered when using Actinoplanes teichomyceticus strain 3/W, the fermentation medium containing Alburex, and the fermentation time 275 hours. The new product was separated from teicoplanin complex by polyamide resin chromatography and purified by Amberlite XAD-7 and affinity resin chromatographies. The structure was established on the basis of the physico-chemical characteristics of the complex and of its aglycone. The new structure is that of teicoplanin with a carbonyl group substituting for the CHNH2 group of amino acid 1. We hypothesize that the novel complex is a transformation product of teicoplanin due to a simple transamination reaction, as supported by its structure and by the concomitant decrease in teicoplanin concentration during its production.