The aim of this paper is to study a decomposition of finite T0 spaces into topological entities called chains and cells. These objects behave like complete units under homeomorphisms and they appear to be useful in investigating certain aspects of finite spaces. As an elementary illustration of how these entities can be used, the concept of an A 2 space is introduced (in the next paragraph) and it is demonstrated that the order of the automorphism group of an A 2 space is expressible as 2t , for some t ≧ 0.