This study was carried out to evaluate the chemical and phenolic contents of some by- products tomato pomace powders (TPP), mango seeds kernel powder (MSKP), and pomegranate peels powder (PPP), Also the effect of substitution of wheat flour with 2.5, 5.0, 7.5 and 10% of (TPP), (MSKP), and (PPP) on chemical, phenolic contents and sensory characteristics of biscuits was studied. Results showed that, wheat flour showed higher moisture and total carbohydrate contents. Tomato pomace powder showed high crude protein, and crude fiber contents. Mango seeds kernel powder had the highest lipids content and pomegranate peels powder had the highest ash and crude fiber contents. For total phenolic and flavonoid content, TPP contain the highest total phenolic and flavonoid content followed by PPP and finally MSKP. Also, the partial replacement of wheat flour with TPP, MSKP and PPP increased chemical composition percentage (moisture, crude protein, lipids, ash, and crude fiber), minerals content (i.e., K, Ca, Mg, Na, Mn, Fe, and Zn) and dietary fiber content (i.e., total, soluble and insoluble dietary fibers) of biscuit samples. However, total carbohydrates were decreased in parallel with increasing the level of substitution compared with control biscuit samples. Biscuit treatments containing TPP, MSKP and PPP had recorded the same minerals dietary fiber content. The partial replacement of wheat flour with TPP, MSKP and PPP increased total phenolic and flavonoid contents of biscuit samples compared with control sample in parallel with increasing the level of substitution. Biscuit treatments containing TPP had the highest total phenolic and flavonoid contents followed by PPP and finally MSKP treatments. The sensory evaluation characters, taste, colour, appearance, crispness, and overall acceptability, have no significant difference between the control sample and biscuit samples which substituted with 2.5, 5, and 7.5% of MSKP and TPP.