In the title rhodium(I) complex, [RhCl(C(8)H(12))(C(5)H(12)N(2)S)], N,N'-diethyl-thio-urea acts as a monodenate S-donor ligand. The rhodium(I) coordination sphere is completed by the Cl atom and the COD [= 1,5-cyclo-octa-diene] ligand inter-acting through the π-electrons of the double bonds. If the midpoints of these two bonds are taken into account, the Rh atom exhibits a distorted square-planar coordination. The syn conformation of the N,N'-diethyl-thio-urea ligand with respect to the Cl atom is stabilized by an intra-molecular N-H⋯Cl hydrogen bond. A weak inter-molecular N-H⋯Cl inter-action links mol-ecules along the a axis.