A new rhenium(III) complex, [Re(SC(NH 2 ) 2 ) 6 ] 3 + , has been prepared by reduction of perrhenate with tin chloride in strongly acidic solution in the presence of thiourea. The complex has been characterized in solution and the solid state by elemental and thermal analyses, electronic and IR spectroscopy, conductimetric measurements, EPR spectra and cyclic voltammetry. Stability in aqueous solution was tested spectrophotometrically. The molecular structure of the complex in the [Re(tu-S) 6 ]Cl 3 4H 2 O salt was determined by X-ray diffraction. The compound is isomorphous to [Tc(tu-S) 6 ]Cl 3 4H 2 O. The rhenium ion, sited at an inversion center, is quasi-octahedrally coordinated by six thiourea sulfur atoms [d(Re--S) vary from 2.412(2) to 2.429(2) 9]. Average thiourea bond distances are similar to those observed for the Tc analog [d(S--C) = 1.746(8) and d(C--N) = 1.32(1) 9].