Abstract: An indirect fluorimetric method for the determination of traces of mercury is presented. This method is based on the reaction between mercury ion and fluoresceinmercuric sulfide liberating a fluorescence in a neutral or weakly alkaline medium. The intensity of fluorescence is measured at 519 nm with an excited wavelength at 499nm. The determination of mercury in the range ppb-ppm in air, water and soil is described. The method is simple, rapid and highly selective. The limit of detection for mercury is 10^-9 g Hg per ml. The relative standard deviation is 8.4-0.7%.