The synthesis of sialic acid containing glycoconjugates remains a challenge in carbohydrate chemistry, impeding the cultivation of biological and therapeutic potentials of sialo-glycans. We have long been seeking for a robust method for the synthesis of sialo-glycolipids such as gangliosides. In the earlier part of this paper, I will describe the synthesis of highly complex gangliosides mainly found in echinoderms, which possess neuritegenic activity. The syntheses were successfully achieved based on the highly reactive synthetic units that were developed in our group; N-Troc-sialyl donor, 1,5-lactamized sialyl acceptor and glucosyl ceramide [1-3]. The synthetic units also allowed for the synthesis of fluorescently labeled gangliosides useful for single molecular imaging of lipid raft domain in the cell membrane [4-7]. In the later part, I will report a robust and comprehensive method for selective α-glycosidation of sialic acid, in which bicyclic sialic acid was utilized as the synthetic equivalent of the bridgehead oxocarbenium cation to direct α-glycoside formation [8]. This method ensured fully α-selective sialidation with a broad spectrum of hydroxyl compounds in high yields. Furthermore, the C-glycoside formation of sialic acid and the synthesis of oligomeric sialic acid have been achieved.