Crystals of the tetrasaccharide, (2,3,4,6-tetra- O-acetyl-β- d-glucopyranosyl)-(1 → 3)-[2,3,4,6-tetra- O-acetyl-β- d-glucopyranosyl-(1 → 6)]-(2,4-di- O-acetyl-β- d-glucopyranosyl)-(1 → 3)-1,2,4,6-tetra- O-acetyl-β- d-glucopyranose, belong to the monoclinic system, space group P2 1, with a = 12.709(4), b = 27.767(9), c = 9.567(4) Å, β = 105.07(2)°, and Z = 2. The crystal structure was solved by the direct method and refined by the full-matrix least-squares procedure to an R-value of 0.071 for 3029 observed reflections in the X-ray data. All the four d-glucopyranose residues have the usual 4 C 1 chair conformations. The torsional angles at two (1 → 3)-β-linkages were φ(O-5-C-1-O-1-C-3) = −74° and ψ (C-1-O-1-C-3-C-2) = −122° between the nonreducing and the middle residues, and φ = −67°, ψ = −111° between the middle and the reducing residues. The orientation about the (1 → 6)-β-linkage was found to be φ (O5-C1-O-1-C-6) = −77°, θ(C1-O-1-C-6-C-5) = 160°, and χ (O-1-C-6-C-5-O-5) = 63° ( gt conformation). The primary acetate groups at C-6 of the reducing and the (1 → 6)-branched residues were in the gt conformations (O-5-C-5-C-6-O-6 = 81° and 84°, respectively). On the other hand, the gg conformation was observed for the primary acetate group in the nonreducing residue (O-5-C-5-C-6-O-6 = 78°).