Raman spectra have been studied in single crystals of RuS_2 at room temperature. Three, out of the five vibrational modes predicted from a group-theoretical analysis are observed. An analysis based on scattering intensity tensors is made to assign the observed peaks in the spectra. A comparison of Raman and infrared frequencies indicates that the sulfur-sulfur bonds and metal-sulfur bonds in RuS_2 and FeS_2 are of comparable strength.