The Minamata disease was discovered in the Minamata region, Kumamoto Prefecture, Japan, in 1956. Symptoms of this disease included cerebellar ataxia, sensory disturbance, narrowing of the visual field, and hearing and speech disturbances. In 1965, similar conditions were identified in persons living around the Agano River area, Niigata Prefecture, Japan and accordingly termed as the Niigata Minamata disease or the second Minamata disease. Both the diseases have been attributed to poisoning with methyl mercury that was generated during the production of acetaldehyde using mercury as a catalyst. The discharged methyl mercury accumulated in fishes and shellfishes and caused poisoning on consumption. This review discusses the history, clinical presentation including atypical forms, and autopsy findings of the Niigata Minamata disease. In addition, it highlights the problems about criteria for official recognition and the therapeutic trial for this disease.