Given the strong association of the apolipoprotein E (apoE) allele epsilon 4 (epsilon 4) with Alzheimer's disease or cognitive decline in elderly, we tested whether cognitive performance in schizophrenic subjects is associated with an increase in the frequency of the ApoE epsilon 4 allele. Our data indicate that in our sample: (1) there is no association between schizophrenia and the ApoE epsilon 4 allele; and (2) the ApoE epsilon 4 allele is not of major importance with regard to the cognitive decline observed in schizophrenia.