An almost completely decomposable (acd) group is a finite rank torsion-free
abelian group containing a finite direct sum of rank-1 groups as a subgrou
p of finite index. This paper is devoted to a determination of the represen
tation type of indecomposables in categories of acd groups. In the process,
representation types of categories of related representations of finite pa
rtially ordered sets (posets) over the rings Z/p(j)Z and Z(p), the localiza
tion of the integers Z at a prime p, are also determined.