Cell adhesion molecules ere classically known to be key players in a whole array of biological functions during development through cell-cell and cell-substratum adhesion. Accumulating evidence suggests, however, that the functional significance of adhesion molecules may extend well beyond embryonic development into adult stage. The aim of this article is to review our current knowledge on the implications of adhesion molecules in various cognitive processes. Particular emphasis as placed on the immunoglobulin superfamily of adhesion molecules, which are found to be involved in activity- dependent plasticity of the nervous system, and hence promising candidates in modulating cognitive functions.