Fluorous-tagged saccharide primers could be viable scaffolds for the synthesis of oligosaccharides. This research demonstrates that a fluorine-containing saccharide derivative could actually be taken up by the cell, the saccharide chain elongated by cellular enzymes, and the elongated product released by the cells to the culture medium. A fluorous-tagged lactoside primer, 6-(perfluorohexyl)hexyl-4-O-(beta-D-galactopyranosyl)-beta-D-glucopyranoside, was chemically synthesized and introduced in mouse B16 cells to prime oligosaccharide synthesis. Uptake of the primer by B16 cells resulted in the sialylation of the terminal galactose residue to afford an oligosaccharide with the same glycan structure as ganglioside GM3. The presence of many fluorine atoms did not have any adverse effects to the cells. Moreover, the number of fluorine atoms did not pose a steric barrier and instead, their presence possibly increased the hydrophobicity of the primer and enhanced membrane permeability. This strategy of using a fluorous-tagged primer and cells can pave the way for an easier way of preparing oligosaccharides via an environment-friendly approach that eliminates the use of large amounts of organic solvents.