In the present study the effect of the addition of prebiotic, raffinose, on the main physicochemical characteristics of yogurts after storage at 4 ^oC for 4 weeks was studied. More specifically yogurts were produced using the probiotic microorganism Lactobacillus casei ATCC 393 in combination with the traditional yogurt culture Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. Four different types of yogurts were produced with the addition of 0, 0.5, 1 and 2 % w/v raffinose. During storage of yogurts several physicochemical characteristics were monitored such as pH, titratable acidity, syneresis and water holding capacity. No significant differences were observed in physicochemical characteristics with the addition of raffinose. The organoleptic evaluation of the produced yogurts revealed the superiority of yogurts with raffinose and especially those with 1 % w/v raffinose in comparison with the yogurt without raffinose. The use of raffinose retained the viability of probiotic culture in high numbers even after 4 weeks of storage (> 10⁸ cfu g^-1), which is higher than those without raffinose.