The aim of this study was to investigate the effect of different levels of mushroom stalk powder (1.0%, 2.0%, and 3.0%) on the viability of probiotic starter culture , physicochemical, rheological and sensory properties of low fat probiotic yogurt (1% fat). Low fat yogurt samples were stored at 5 ± 1˚C, analyzed when fresh and after 5, 10 and 15 day. The results showed a gradual increase in the values of pH, dietary fiber, viscosity, phenolic content and radical scavenging activity of low-fat yogurt with increasing proportion of mushroom stalk powder added. On the other hand, the values of acidity and synersis decreased by increasing the proportion of mushroom stalk powder. The survival of Lactobacillus acidophilus, Streptococcus thermophilus and Bifidobacterium bifidum decreased during storage time in all yogurt treatments, although it stood at recommended levels for health effects (at least 106 cfu/mL in traditional yogurt). Low fat yogurt that containing of 2% of mushroom stalk powder were the highest of sensory properties than the other treatments. Thus, the study demonstrates that mushroom stalk powder can be used as a source of dietary fiber and phenolic compounds in low fat yogurt at a rate of 2% which enhanced its nutritional value, rheological and sensory properties.