The second-order hyperpolarizabilities (beta) of two categories of organic ionic species were evaluated by the hyper Rayleigh scattering method. The beta of (dimethylamino)stilbazolium analogues in methanol with long cut-off wavelength more than 600 nm, which can be used for electro-optic modulation, were evaluated to be in the order of 10(-27) esu using 1064 nm light as a fundamental beam. Aromatic sulfonates in the second category were found to have comparatively large beta values irrespective of short cut-off wavelength : In the case of sodium p-toluenesulfonate with cut-off of 280 nm, beta in methanol was 2.2x10(-29) esu and was about two thirds of p-nitroaniline with cut-off of 445 nm.