Two-dimensional temperature measurements using filtered Rayleigh scattering (FRS) have been demonstrated. A tunable single-longitudinal-mode alexandrite laser was employed to provide the tunable narrow-line-width ultraviolet laser beam at 254 nm. Isotopic-enhanced mercury was utilized as an ultraviolet atomic filter. The strong absorption of the filter enabled effective suppression of elastic background. The transmission curve of the mercury filter was characterized by combining experimental measurements and proper modeling. The Rayleigh–Brillouin spectral profiles were calculated employing the S6 model. Quantitative interpretations of two-dimensional FRS signals were performed in both premixed and diffusion flames. The temperature values obtained were in good agreement with adiabatic calculations and earlier measurements.