The new complex [Co(pyr)(2)(sal)(2)].H2O (pyr = pyridine, sal = salicylaldehyde) has been synthesized and its crystal structure was determined to be monoclinic system with space group C2/c by single-crystal X-ray diffraction. a = 14.654(3), b = 12.247(3), c = 14.060(3) Angstrom, beta = H 6.804(4)degrees, V = 2252.1(8) Angstrom(3), Z = 4, D-c = 1.408 g/cm(3) and mu = 0.800 mm(-1). In the crystal the Co(II) ion is six-coordinated to form an octahedral polyhedron.