Two novel glycosphingolipids were isolated from Sphingomonas paucimobilis and their structures were completely elucidated. The glycosyl portion of the glycosphingolipid consists of an alpha-D-Manp-[1----2)-alpha-D-Galp-(1----6)-alpha-D-GlcpN-(1 ----4)-alpha-D- GlcpA-R tetrasaccharide. The hydrophobic residue R was found to be heterogeneous with respect to the dihydrosphingosine residue. Erythro-1,3-dihydroxy-2-amino-octadecane and erythro-1,3-dihydroxy-2-amino-cis-13,14-methyleneoctadecane were identified in comparable amounts. Both dihydrosphingosine derivatives were quantitatively substituted by an (S)-2-hydroxymyristic acid in amide linkage.