The rhodium-silicon phase diagram was investigated by means of X-ray powder diffraction, differential thermal analysis, metallography and electrical resistivity measurements. The existence of nine intermetallic phases was established: Rh 2Si, Rh 5Si 3, Rh 20Si 13, Rh 3Si 2, RhSi-l, RhSi-h, RhSi-x, Rh 4Si 5 and Rh 3Si 4. Rh 20Si 13 is a high temperature phase which decomposes eutectoidally at 1050 ± 20 ° C. At the stoichiometric composition RhSi, three different structures were found: an orthorhombic low temperature phase (RhSi-l), a cubic high temperature FeSi-type phase (RhSi-h) and a monoclinic and probably martensitic phase (RhSi-x). The CsCl-type RhSi mentioned in the literature was not found in this study. One of the phases, Rh 4Si 5, is superconducting.