The magnetic moment of cobalt(II) fluorosulfate has been measured over the temperature range 312 to 120 °K and the results agree with theory for cobalt(II) in a regular octahedral ligand environment with λ equal to the free-ion value and no reduction in the magnetic moment due to electron delocalization. From its electronic spectrum, values of the ligand-field parameters Dq and B are estimated to be 765 and 860 cm−1, respectively. The infrared spectrum shows no distortion of the fluorosulfate groups from C3v symmetry.