Trimeric sialic acid [Neu5Acα(2→8)Ncu5Acα(2→8)Ncu5Ac. 1] residue-containing gangliosides, GT4, α(2→6)GT4 and GT3, have been synthesized for the first time. Methyl [phenyl (3) was prepared from 1, via lactonization, methyl esterification of the carboxyl group at the reducting end, O-acetylation and conversion of the anomeric acetoxy group into a phenylthio group. Iodonium-promoted glycosylation of 3 with 2-(trimethylsilyl)ethyl (5), 2-(trimethylsilyl)ethyl (6), 2-(trimethylsilyl)ethyl (9), and 2-(trimethylsilyl)ethyl (11) gave the corresponding tetrasaccharides (13–15, 17) having the (Neu5Ac)₃-Gal structure. The peracylated oligosaccharides 18 and 24 derived from 13 and 17, and the previously reported lactose derivative 29 were converted into the α-trichloroacetimidates 20, 26 and 31, and coupled with (2S,3R,4E)-2-azido-3-O-benzol-4-octadecene-1,3-diol (21) to afford the corresponding β-glycosides 22, 27 and 32. These protected azidosphingosine derivatives were each transformed into the target gangliosides GT4, α(2 → 6)GT4 and GT3 via selective reduction of the azido group. subsequent coupling with octadecanoic acid, O-deacylation and saponification of the methyl ester and lactone groups.