Chapter 11 discusses the properties of Raman response functions in d-wave superconductors. It is shown that the vertex function of high-symmetric A1g mode is strongly modified by the screening effect of the fluctuating charges to the long-range Coulomb interaction. Unlike in an s-wave superconductor, the Raman spectral functions behave quite differently in different symmetric channels in a d-wave superconductor. Particularly, the B2g-mode shows a characteristic peak at a higher frequency than that of the B2g mode. The behavior of the Raman response function in a two-band system, such as the electron-doped cuprate superconductors, is also discussed.