Specific apolipoprotein E alleles have been associated in the last few years with several diseases using appropriate controls. However, these control groups are rarely representative of the general population since they correspond either to aged or healthy control groups (and thus depleted of pathological alleles). For this reason it is difficult at present to compare population allelic frequencies in different countries. In order to provide this essential basic data representative of the general population, in this work we have determined the distribution of apolipoprotein E alleles in 226 individuals from the population of Catalonia (Spain) sampled with the main purpose of paternity testing. The allelic frequencies are: epsilon2 = 0.064, epsilon3 = 0.810 and epsilon4 = 0.126, predicting a lower incidence of Alzheimer disease and possibly also of other pathologies where this allele is a risk factor.