ne characterization of the local temperature of the liquid phase of a polydisperse spray is an important problem in many engineering applications. This article presents a new technique to measure the temperature of the liquid phase in polydisperse sprays, even under evaporation. The technique is based on the use of laser-induced fluorescence of a dye tracer (sulfo-rhodamine B) added to the liquid. The fluorescence emission is detected simultaneously on three spectral bands in order to eliminate the dependency of the fluorescence emission on the concentration of the tracer, on the dimensions of the probe volume, on the laser intensity, and on the optical layout and also to correct for the wavelength-dependent scattering of the fluorescence. This effect is due to the interaction of the fluorescence photons with the spray environment. As an example, application to a heated water polydisperse spray is presented.