We report a patient with an acute, self-limiting neuropathy consisting of ataxia and areflexia, but without ophthalmoplegia or limb weakness, with transient, high-titer serum IgG antibodies to a single NeuAc(alpha 2-8)NeuAc-linked disialosyl epitope, as found on GD1b and GD3 gangliosides. The serum did not react with GQ1b, GT1a, or GT1b. This atypical case, which most closely represents an incomplete Miller Fisher syndrome, indicates that anti-GD1b/GD3 antibodies may be able to induce sensory ataxia.