Abstract: A leak detectable refrigeration composition including a polyhalogenated hydrocarbon refrigerant, a refrigeration oil, or a mixture of the two having a fluorescent dye dissolved therein, is prepared for use in refrigeration systems in automobile air conditioning systems, commercial refrigeration systems, and the like. Upon exposure to ultraviolet light, there is sufficient fluoresence by the refrigeration liquid to allow one to visually detect a leak in the system due to the presence of the dye at the source of the leak. Small leaks which were previously nondetectable with dye coloring systems detectable in normal light may now be detected due to the greater visibility of the flourescent dye under an ultraviolet light.