The effects of substituting milk fat with different levels of inulin as a fat replacer on the chemical, microbiological and sensory characteristics of yoghurt were examined.Samples of yoghurt were kept in refrigerator at(5± 2Cº), and examined when fresh, and after 2, 3 and 7 days of storage. Chemical composition, microbiological contents and sensory characteristics were examined. The obtained results indicated that addition of inulin resulted in a significant increase in the total solids, moisture contents, and the development of titratable acidity. On the other hand, less whey syneresis was observed during the storage of the yoghurt samples.  On the other hand, replacing of milk fat by inulin was of no significant effect on the fat content.Addition of inulin stimulated the growth of lactic acid bacteria. The colony forming units of total bacterial counts, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus increased up to the 3^rd day of storage period, followed by decrease up to the end of the storage period. Sensory evaluations were almost stable during the first 7^th days of storage, then decreased slightly until the end of storage the period. Yoghurt samples containing 1.2% of inulin showed minor difference in the sensory characteristics, compared with control, and of the most acceptable sample. In conclusion, inulin could be successfully used as a fat replacer in making of low fat yoghurt with additional nutritional benefits without affecting the physico-chemical properties of yoghurt.