In the title complex, [Co(C4H7N2O2)2Cl(C6H7N)]·0.5H2O, the central CoIII ion, chelated by four N atoms of the two bidenate glyoximate ligands, exhibits a slightly distorted octahedral geometry. The axial positions are occupied by a chloride ion and the 4-methylpyridine N atom. Intermolecular O—H⋯O hydrogen bonds link the molecules in the crystal via the water molecules, while the glyoximate ligands exhibit intramolecular O—H⋯O hydrogen bonds.