The carbon-13 n.m.r. spectra of acyclic carbohydrate derivatives, namely alditols. 1,2-bis(phenylhydrazones), dithioacetals, and related acyclic sugar derivatives, are reported. The study has corroborated earlier results, based on 1H n.m.r. investigations, on the conformational behaviour of such compounds in solution. Application of this technique in elucidation of regiospecificity of oxidation of alditols by Acetobacter suboxydans is discussed.