The transitional phase inversion of BrijL4/isopropyl myristate/water emulsions is detected by monitoring the visible light backscattering (LBS) using an optical fiber. For comparison, electrical conductivity is simultaneously monitored during the heating-cooling cycle. The LBS signal exhibits always a minimum near the phase inversion temperature value determined with conductivity. The LBS results are also analyzed in terms of the Winsor type for equilibrated systems and particle size of O/W emulsions. The LBS signal points out a transparency area for inversion through the Winsor IV type and thus allows us to determine the X point of the fish diagram for equilibrated systems more quickly. The LBS signal presents a maximum for the average diameter of O/W emulsions of around 1 mu m and depends on the particle size distribution. The use of a commercial visible light backscattering optical fiber thus exhibits several advantages over the classical conductivity measurement for transitional inversion phase emulsification process monitoring.