The effects of acidity (pH 5.0 to 7.0) and protein concentration (0.5 to 2.0%) on coalescence stability of o/w emulsion stabilised by alpha-lactalbumin (alpha-La), that was salted out from rennet whey with 7% NaCl at pH 2.0, were studied Irrespective of pH and alpha-La concentration, the Sauter diameter (D(vs)) of an oil droplet was found to increase on storing the emulsion for 4 h at room temperature and the conditions preventing from creaming and accelerating destabilisation of the emulsion. The effect of pH on emulsion coalescence stability was greater than that of protein concentration.