A number of new Co(III) dimethylglyoximates containing N- pyrimidinylsulfanilamides were obtained. These complexes of the general formula [Co(N ₃)(DH) ₂L] (I-V) (where DH is the dimethylgly- oxime monoanion and L are N-pyrimidinylsulfanilamides NH ₂-C ₆H ₄-SO ₂-NH-R with different substit- uents R) are expected to have antibacterial properties. Their structures were examined by IR, electronic absorption, and NMR spectroscopy and X-ray diffraction. They were classified among cobalt(III) trans diox- imates. In all the complexes obtained, the cobalt atom coordinates to four N atoms of two dimethylglyoxime residues. The octahedral environment of the metal atom is completed with the amino N atom of the neutral molecule L and the N atom of the azide anion. In the crystal structures, complexes I-V are united through intermolecular hydrogen bonds N-H-O, N-H-N, and O-H-O, in which the groups -NH ₂ and =NH of the ligand L and water molecules (for I, IV, and V) serve as proton donors.