Whereas the definition of B-cell memory is based on well-known cellular properties and differentiation steps, the process of T-cell memory generation was, until recently, less well understood. A series of recent reports, however, have drastically modified our notion of CD8⁺ memory T cells. They show that, in addition to division, the generation of efficient memory cells requires a previously unknown differentiation process. As a whole, the generation of CD8⁺ memory T cells appears to mimic the generation of memory B cells. Both processes depend on the help of CD4⁺ T cells, they are irreversible, they have the same mechanism, and they occur progressively during the late expansion phase of the primary immune response.