We report a 43-year-old woman who died after 18 years history of parkinsonism. She was well until 25 years of the age (1976) when she noted a difficulty in stepping her feet. In the next year, she started to drag her feet. She was treated with levodopa with good response, however, she developed dyskinesia when she was 33 years of the age. She was evaluated in another hospital in 1984. She showed normal intelligence, normal ocular movement, masked face, small voice, small step gait, stooped posture, freezing of the gait, retropulsion, and cogwheel rigidity in limbs. No tremor or ataxia was noted. She received left ventrolateral thalamotomy at that time. Rigidity on the right side markedly reduced, however, she continued to show bradykinesia and motor fluctuations. On August 1 of 1994, she developed fever of 40 degrees C and dyspnea. On the next day, she expired from acute respiratory distress. She was able to walk unsupported until just before her last admission. The patient was discussed in a neurological CPC. The chief discussant arrived at the conclusion that this patient had Lewy body-positive young onset Parkinson's disease. Opinions were divided into two groups, i.e., young onset Lewy-body positive Parkinson's disease and Lewy-body negative young onset parkinsonism. Post-mortem examination revealed moderate loss of pigmented neurons in the substantia nigra more in the ventro-lateral part. Lewy bodies were found in the remaining neurons. Lewy bodies were more frequently seen in the locus coeruleus, although neuronal loss was less prominent in the locus coeruleus. The dorsal vagal motor nucleus showed moderate loss of neurons. Otherwise, the central nervous system was unremarkable. To our knowledge, this patient had the second youngest age of the onset so far reported in the literature for Lewy-body positive typical Parkinson's disease.