Fruits and vegetables play an important and vital role in human’s life by their essential and significant amounts of nutrients and bioactive compounds, which are distributed in all of the fruit parts and particularly concentrated in peels, seeds and kernels, known as "by-products". In this study, 13 samples of fruit and vegetable by-products were investigated "orange, mandarin peels and seeds, pomegranate peels, mango peels and kernels, guava seeds, carrot, potato, green pea, onion peels and okra by-products", which are commonly used in domestic and food processing industries. The gross chemical composition was investigated; carbohydrates were abundant component in the peel, its content were related in pomegranate, mandarin, orange peels and mango peels and kernels samples ranged from (78.72 to 71.74%), crude fats and fiber were prevalent component in seed samples, orange and mandarin seeds had the highest content of crude fat (40.94 and 40.65 %), respectively. Guava seeds had the highest content of crude fiber (60.24%). Bioactive compounds such as ascorbic acid, total phenol, and total flavonoids and tannins contents were investigated. The results indicate that the bioactive components were detected in sample extracts but their contents varied in different samples. In general, total phenols were the highest concentration in both fresh and dried samples; pomegranate, mango peels and mango kernels had the highest content of total phenols (8.88, 7.21 and 8.99 mg/g, respectively) in fresh samples and (37.66, 27.62 and 24.75 mg/g, respectively) in dried samples. The antioxidants activities of methanolic extracts were measured using DPPH as free radical and the ability of by-product antioxidant extract to scavenge it. The results exhibit considerable degrees of activities towards scavenging of DPPH free radical, as well as. Mango kernels, pomegranate and mango peels exhibit the highest degree of activity with IC50 (21.62, 31.09 and 27.19µg/ml of extract) from fresh by-product samples and (18.79, 20.99 and 5.88 µg/ml of extract) from dried by-product samples for pomegranate, mango peels and mango kernels, respectively.