A 24-year-old carpenter had the shakes and fever on March 13, 1990. He suffered from watery diarrhea on March 14 and 15. He left muscle weakness in his thumbs and fingers when he drove nails with a hammer on March 24. The weakness reached maximum by the 3rd day of illness. He was admitted to our hospital on day 4. Neurological examination revealed symmetrical weakness localized in the intrinsic hand muscles (MRC grade 2-4). The deep tendon reflexes were preserved. Sensation was intact except for mild disturbance of superficial sense on both plantar areas. Campylobacter jejuni was cultured from his stool. A complement fixation test indicated serologically preceding C. jejuni infection. Whereas maximum motor nerve conduction velocities were not reduced and distal latencies were not prolonged, compound muscle action potential recorded in the thenar and hypothenar muscles were remarkably reduced on day 5. Needle EMG showed neuropathic changes in four limbs. Sensory nerve conduction velocities and action potentials were normal. The weakness gradually improved in association with increased compound muscle action potentials in the thenar and hypothenar muscles. His muscle symptom fully resolved 2 months after the onset of his illness. Thin-layer chromatogram with immunostaining revealed that serum IgG from this patient reacted with GM1, GD1a, GD1b, but did not react with GM2 and GT1b. Enzyme-linked immunosorbent assay showed that anti-GM1, GD1a, GD1b antibodies titer (IgG) decreased concurrently with the clinical improvement.