Apolipoprotein E (apo E) epsilon4 is a risk factor for sporadic and late-onset familial Alzheimer's disease, but it is not well known whether the apo E is associated with spinocerebellar degeneration. We studied the frequency of apo E allele in 59 olivopontocerebellar atrophy (OPCA) patients, including 13 pathologically confirmed cases. The distribution of the apo E allele frequency did not differ between OPCA patients and controls. Apo E allele does not influence the development of OPCA.