Results are reported of high-precision measurements on electric and magnetic properties of the isotopic species of carbonyl sulphide by molecular-beam electric-resonance spectroscopy. The properties obtained are the electric dipole moment, the molecular magnetic moment, the anisotropy in the magnetic susceptibility, the molecular quadrupole moment, and the spin-rotation constant and the magnetic shielding anisotropy for the C-13 nucleus in (OCS)-O-16-C-13-S-32.