Raman spectra are reported for liquids and Langmuir films enhanced by the electromagnetic fields of plasmon surface polaritons at flat silver surfaces. The Kretschmann prism coupling configuration is used to excite the incident surface polariton and to couple out the Raman shifted surface wave. The spectra are interpreted with the help of a simple quantum theory and compared with previously reported grating spectra. Enhancement factors, polarization characteristics, and the feasibility of using surface polaritons to enhance the Raman spectra of adsorbates on flat electrodes in contact with aqueous electrolyte are discussed. © 1984 American Institute of Physics.