  Asymptotically cylindrical Ricci-flat manifolds play a key role in
constructing Topological Quantum Field Theories. It is particularly important
to understand their behavior at the cylindrical ends and the natural
restrictions on the geometry. In this paper we show that an orientable,
connected, asymptotically cylindrical manifold (M,g) with Ricci-flat metric g
can have at most two cylindrical ends. In the case where there are two such
cylindrical ends then there is reduction in the holonomy group Hol(g) and (M,g)
is a cylinder.
