In the title complex, [Cu(C(10)H(12)NO(4)S)(OH)(C(10)H(8)N(2))]·0.5H(2)O, the Cu(II) ion shows a distorted square-pyramidal coordination geometry with two N atoms from the 2,2'-bipyridine ligand and one N and one O atom from the N-tosyl-α-alaninato ligand forming the basis of the coordination polyhedron and another O atom of the hydroxo group acting as the apex of the pyramid. The solvent water mol-ecule is statistically disordered over two positions.