Saccharomyces cerevisiae KA01 was isolated from palm wine obtained from a local brewer in Songkhla province, Thailand. Mannoproteins with emulsification properties were extracted from the cell walls of S. cerevisiae KA01 cultivated in YM medium by autoclaving in a pH 7.0 citrate buffer for 60 min with a yield of 0.32 g/g wet cells. The mannoprotein extract obtained was evaluated for its chemical and physical stability to establish its potential use as a natural emulsifier in processed foods. The mannoprotein extract exhibited emulsion with the vegetable oils tested and showed emulsion activity of 65% towards palm oil as oil-in-water with a critical emulsifier concentration of 20 g/l. The mannoprotein extract had similar emulsifying properties to the commonly used food emulsifiers gum arabic and lecithin. Palm oil-in-water emulsions were stabilized over a broad range of conditions from pH 5 to 8 with up to 3% (w/v) sodium chloride and up to 0.1% (w/v) CaCl2 and MgCl2 in the aqueous phase. Temperature did not affect the emulsion activity of the mannoprotein extract. Preliminary trials showed that mannoproteins from S. cerevisiae KA01 had potential for use in salad dressing.