Alzheimer's disease (AD) is the most common human progressive dementia linked, in its sporadic form, to a common polymorphism within a gene for apolipoprotein E (APOE) mapped to chromosome 19. Individuals with APOE 4 isoforms are more prone to develop sporadic from of AD than those who carry APOE 2 or APOE 3 alleles. As distribution of APOE isoforms in Poland is unknown, we decided to study it in AD and control cases. In AD group, three patients (23.1%) were homozygous for APOE 4, four cases (30.8%) were heterozygous and six cases (46%) carried no APOE 4 allele. In control group (n-11), only one case (9.1%) was homozygous for APOE 4 allele, no case was heterozygous for APOE 4 while 10 cases (90.9%) carried no APOE 4 alleles. Our results are virtually identical to those reported from Western countries.