The specific lipopolysaccharide of Chromobacterium violaceum (NCTC 7917) was extracted from acetone-dried cells with warm aqueous phenol. Mild acid hydrolysis of the lipopolysaccharide resulted in the separation of a specific degraded polysaccharide from a chloroform-soluble phospholipid. The lipopolysaccharide contains a new 2-amino-2-deoxyaldose sugar which occurs naturally as its N-acetyl derivative; glucosamine, D-glycero-D-mannoheptose, glucose and galactose are also present. Glucosamine is not present in the degraded polysaccharide. The acid-hydrolysate of the degraded polysaccharide was separated into neutral and amino sugar fractions by passage through Zeo-Karb 225 resin. The crystalline hydrochloride of the new amino sugar was isolated, and, by elementary analysis, deamination, periodate oxidation and examination of its phenylosazone, it was shown to be 2-amino-2:6-dideoxy-D-galactose hydrochloride (D-fucosamine hydrochloride).