The quinoa is pseudocereal plant that has nutritional value. Recently, It was cultivated in iran because of water crisis. This study aimed to assess the physicochemical and antioxidant properties of quinoa cultivated in Iran for the first time. The macronutrients and energetic value, polyphenol, total phenol content and DPHH of quinoa were measured. Some B group vitamin, the free fatty acid profile was assessed by HPLC and GC-mass separately. The trace elements were also evaluated by ICP. The amounts of dry matter, protein, fat, ash, and available carbohydrates were, 90.33±0.89, 16.30±1.52, 6.09 ±0.30, 4.43±0.47, and 73.14±1.59 percent, respectively. The total bacterial count of quinoa was 5.22±0.23 (LOG₁₀ CFU.g^-1). Escherichia coli and sulphite-reducing clostridia were lower than 1.0 (LOG₁₀ CFU.g^-1). Salmonella was absent in all samples. According to the DPPH method, the IC₅₀ of quinoa seed was approximately 6232.0 mg.L⁻¹ compared to the equivalent Gallic acid as a standard (IC₅₀: 184.15 μg.mL⁻¹). Also, the quinoa seed contained the highest level of niacin (0.881 mg/100g) among the vitamin B groups. The analysis of the amino acid profile revealed the highest contents of glutamic acid (1.230 g/100g) and lysine (3.08 g/100g). The concentrations of minerals including calcium, magnesium, and potassium were respectively (0.07, 0.086 and 0.35 g/100g). Quinoa is a valuable nutritional product that can provide health benefits to the human, mainly because of its linoleic acid content.