The paper presents a comprehensive experimental study on emulsion (oil-in-water) fluid flow through curved diffusers. The experimental setup was designed and constructed in the fluid mechanics laboratory of the faculty of engineering, Minoufiya University to perform the measurements which have been carried out on five models of curved diffusers. The measurements of pressure distributions along the outer and inner walls of the curved diffuser were performed for different area ratios, different curvature ratios (ratio of centerline arc radius to inlet width), different inflow Reynolds numbers and different emulsion holdup (ratio of oil volume to emulsion volume), while the oil concentration was varied from 0% to 20% by volume. The experimental work was carried out using two sets of oil-in-water emulsions; the first is stabilized o/w emulsion using Sodium Dodecyl Sulfate (SDS) emulsifier and the second is unstable (oil-in-water) emulsion at different holdup values. The energy-loss coefficients for each model are based on detailed measurements of the wall pressure distributions along walls of the curved-diffuser models including long upstream and downstream tangents. The energy-loss coefficient data were plotted as a function of Reynolds number for the tested models at different concentrations. New results on energy-loss coefficient during flow of destabilized and stabilized oil-in-water emulsions through curved diffusers are reported in the present paper. The diffuser energy-loss coefficient is strongly affected by the geometrical parameters of diffuser, Reynolds number and emulsion holdup. Generally for the flow in curved diffusers, the resistance coefficients for stable and unstable (oil-in-water) emulsions were higher than that of pure-water flow. It is also noticed that the unstable oil-in-water emulsion exhibits lower values in loss coefficient compared with that given for stable (oil-in-water) emulsion.