  In this paper we consider the real topological K-groups of a toric manifold
M, which turns out to be closely related to the topology of the small cover MR,
the fixed points under the canonical conjugation on M . Following the work of
Bahri and Bendersky [2], we give an explicit formula for the KO-groups of toric
manifolds, and then we characterize the two extreme classes of toric manifolds
according to the two A(1) modules shown in [2].
