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 μm 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.