Quinoa is considered as one of the newly emerged seed with high nutritional and biological aspects. The present research was done to study the biological activities of quinoa seeds. Quinoa seeds (cultivars; Giza1, Red Carina and Sajama) were obtained and their chemical properties were analyzed. Ethanoic extract was prepared and its total phenolic components (TPC), total flavonoid components (TFC), antioxidant and antimicrobial effects were studied. Saponin content was detected using the standard method. The highest contents of moisture, carbohydrate, protein, fat, fiber, ash and iron were found in cultivarSajama (7.23±0.61%), Giza1 (63.45±4.25%), Red Carina (18.11±1.62%), Sajama (10.19±0.98%), Red Carina (5.75±0.51%), Red Carina (5.98±0.46%) and cultivarGiza1 (26.80±2.51), respectively. The mean concentrations of saponin in cultivarGiza1 had the highest concentration of saponin (4.25±0.23 mg/g), while cultivarSajama had the lowest (1.84±0.12 mg/g). CultivarGiza1 had the highest TPC, TFC and antioxidant effects. CultivarGiza1 extract had the highest antibacterial effects. The minimum inhibitory concentrations of cultivarGiza1 (or Misr1) against L. monocytogenes and E. coli bacteria were 10 and 5 mg/ml, respectively, while those of C. quinoa Sajama against L. monocytogenes and E. coli were 80 and 40 mg/ml, respectively. The quinoa seeds are an appropriate alternative candidate of nutrients with high phenolic and flavonoid components and antimicrobial and antioxidant activities. High protein, carbohydrate, ash, fiber, iron, total phenol and flavonoid contents, low saponin concentration and considerable antibacterial and antioxidant effects of the quinoa seeds and particularly C. quinoa Giza1 make them suitable as alternative functional sources of nutrients with high biological effects for human nutrition.