Toric manifolds, a topological generalization of smooth projective toric va
rieties, are determined by an n-dimensional simple convex polytope and a fu
nction from the set of codimension-one faces into the primitive vectors of
an integer lattice. Their cohomology was determined by Davis and Januszkiew
icz in 1991 and corresponds with the theorem of Danilov-Jurkiewicz in the t
oric variety case. Recently it has been shown by Buchstaber and Ray that th
ey generate the complex cobordism ring. We use the Adams spectral sequence
to compute the KO-theory of all toric manifolds and certain singular toric
varieties.