Main studies which have shown an association between the variation in apolipoprotein genes and human neuropsychological impairement are reviewed in this work. Data from literature indicate a special relevance of apolipoprotein E (ApoE) in relation to Central Nervous System (CNS) functions, basically memory. ApoE epsilon 4 is a well documented risk factor for late-onset Alzheimer's Disease (AD). Memory changes in older adults and in AD are also associated with ApoE genotype. Furthermore, ApoE may play a role in formation or degeneration of some neural structures related to memory. In some studies a relation between ApoE's alleles and cerebral vascular disorders like ischemic, haemorrhagic, Vascular (VD) and Multi-infarct (MD) Dementias is also reported. The role of the remaining apolipoproteins in cognitive impairment is still unknown, and these molecules have been considered as risk factors associated with environmental factors in CNS pathologies, essentially the vascular ones.