Oil-in-water (O/W) emulsions have been used as a delivery system to protect conjugated linoleic acid (CLA), a polyunsaturated fatty acid, from oxidation. Conventional gum arabic (GA) and two matured gum arabic samples (EM2 and EM10) were used as emulsifiers to prepare CLA-in-water emulsions. The emulsions have optimal physical and chemical stability at gum concentrations of 5% for all three gums. Emulsions with higher gum concentrations are more susceptible to lipid oxidation. This is attributed to reduced physical stability at higher gum concentrations because of the coalescence and depletion-induced flocculation of the emulsion droplets. The prooxidants iron and copper intrinsically contained in the gums could also contribute to this instability. Among the three gums, EM10 provides the most effective protection for CLA both physically and chemically, because of its superior interfacial properties over GA and EM2.