A new method for oligosaccharide assembly that combines the advantages of one‐pot synthesis and fluorous separation is described. After one‐pot glycosylations are completed, a fluorous tag is introduced into the reaction mixture to selectively “catch” the desired oligosaccharide, which is rapidly separated from non‐fluorous impurities by fluorous solid‐phase extraction (F‐SPE). Subsequent “release” of the fluorous tag and F‐SPE achieved the purification of the desired oligosaccharide without the use of time‐ and solvent‐consuming silica gel chromatography. Linear and branched oligosaccharides have been synthesized with this approach in just a few hours (for the overall oligosaccharide assembly and purification process).