We assessed the apolipoprotein E (ApoE) genotype in 49 sporadic and ten familial Creutzfeldt-Jakob disease (CJD) patients, in seven healthy siblings with a PRNP mutation and in 84 controls. In sporadic CJD, ApoE genotypes and allelic frequencies do not significantly differ from that of controls. No influence of ApoE genotypes on age at onset was found. In familial cases, the disease appeared in mutated subjects showing the same ApoE genotype as members who have not yet developed CJD. Our results provide further evidence that ApoE is not a risk factor for CJD.