Sialic acid is a biologically complex carbohydrate that has important roles in cell signaling, tumour metastasis and glycoprotein stability. The physiochemical properties of sialic acid have made it a valuable resource with an increasing demand in medicine and biotechnology. Currently, sialic acid is only available in limited quantities at high costs. We have metabolically engineered Escherichia coli to produce 1.5 grams of sialic acid per liter of culture at low expenditure, i.e., <$ per gram of sialic acid. First, genes encoding the intrinsic sialic acid transporter (NanT) and aldolase (NanA) were deleted. NanT is required for sialic acid uptake in E. coli, and NanA cleaves intracellular sialic acid into pyruvate and N-acetylmannosamine, which are primary metabolites in bacteria. Removal of NanT and NanA abolishes sialic acid catabolism. Second, a sialic acid biosynthetic pathway consisting of the NeuB and NeuC proteins of Neiserria meningitidis was introduced into the NanT-NanA deficient E. coli strain. NeuC is a hydrolyzing UDP-N-acetylglucsoamine-2-epimerase that converts UDP-N-acetyglucosamine into N-acetylmannosamine. N-acetylmannosamine is condensed with phosphoenolpyruvate by the sialic acid synthase, NeuB, to generate sialic acid. The glucosamine synthase, GlmS, of E. coli was engineered into the NeuB/NeuC pathway to increase sialic acid production from inexpensive sugars including glucose. An optimized sialic acid titer of 1.5 grams per liter of culture was obtained using glucose as feedstock under shake-flask conditions. Sialic acid production from metabolically engineered E. coli is a cost effective and direct route for synthesizing sialic acid and its analogs.