Acute arsenic intoxication may present as Landry-Guillain-Barré syndrome because of similarities in clinical symptoms involving the gastrointestinal tract, weakness, and sensory symptoms. Electrodiagnostic findings may be similar with demyelinating changes predominating early in both diseases. A case is presented of repeated arsenic poisoning over two years misdiagnosed as Landry-Guillain-Barré syndrome. Proximal F-loop latency (M-wave latency at wrist + F-wave latency at wrist - 2 M-wave latency at axilla) helped to establish the correct diagnosis. Serial electrodiagnostic studies were done documenting the evolution of chronic repeated arsenic poisoning from a picture showing demyelination to one with severe axonal loss.