Background and Aims: Hypercholesterolemia is the most important risk factor for cardiovascular diseases. In this study, we compared the effect of consuming probiotic yogurt with that of ordinary yogurt on serum cholesterol level in mildly to moderately hypercholesterolemic subjects. Methods: This randomized and crossover trial included 14 healthy subjects with serum total cholesterol 5.17–7.76 mmol/l. They did not consume yogurt for a 2-week prestudy period and added 300 g/day of milk to their diet. After this period, they were randomly allocated to 2 groups to receive either 300 g of ordinary yogurt or probiotic yogurt (fermented with a starter composed of Lactobacillus acidophilus and Bifidobacterium lactis in addition to bacteria in ordinary yogurt) for 6 weeks as a substitution for milk. After a 4-week washout period, the crossover was made and the study lasted for another 6 weeks. Blood lipid tests were done at the beginning and at the end of each period. Results: Consumption of probiotic yogurt in comparison with ordinary yogurt caused a significant decrease in serum total cholesterol (p < 0.05). Comparison of other blood lipid indices did not show any significant differences between these 2 periods. Conclusion: Yogurt containing two probiotic bacteria strains, L. acidophilus and B. lactis, had a cholesterol-lowering effect in hypercholesterolemic subjects.