Objective: The purpose of the presented study was to describe the proximate chemical composition and content of biologically active components in leaves of two quinoa cultivars (Salcedo and Altiplano) produced in Peru. Methodology: This study conducted by means of different analytical methods. It is describe changes of different phenological stages in relation to nutritional composition, pigment contents, polyphenols, flavonoids and antioxidant activity of plant extract evaluated by standard methods of DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2 -azino-bis-3-ethylbenzthiazoline-6-sulphonic acid) assay and the correlation between mean antioxidant index scores were also analyzed. Results: The results presented no considerable variations. However, the ash content for Altiplano and Salcedo leaves was 2.8 and 3.6%, respectively. The total pigment content is much higher in the Salcedo leaves (4816.77 μg g-1 dry weight) when compared with Altiplano leaves (2662.92 μg g-1 dry weight). The total polyphenol and total flavonoid contents is similar in both samples for Salcedo (10.55 mg GAE g-1 and 8.69 mg rutin g-1) and Altiplano (10.72 mg GAE g-1 and 9.14 mg rutin g-1), respectively. The antioxidant activity as measured by DPPH and ABTS, expressed as Trolox Equivalent Antioxidant Capacity (TEAC), evaluated in Altiplano was higher than that found in Salcedo. The antioxidant potency composite index was 16.32 and 11.95, respectively. The antioxidant potency showed the positive correlation coefficients with phenolics (r2 = 0.6575), flavonoids (r2 = 0.3896) and the correlation between phenolics and flavonoids (r2 = 0.6744). Conclusion: These results indicated promising perspectives for the leaves of two quinoa cultivars (Salcedo and Altiplano) that are excellent resources of bioactive components and can be used in the food industry as infusions.