Amaranthus tricolor(red amaranth) is an important member of the Amaranthus species ubiquitously cultivated worldwide for its valuable constituents. In this study, the determination of important nutrients, minerals,amino acids,phytochemicals,carotenes, antiradical activity, and antibacterial activity of the entire part of the redamaranthplant was performed. The analysis of the nutritional composition of the whole part of red amaranth shows that there was an appreciable quantity of protein (26.60 ± 0.42%), fat (4.49 ± 0.30%), fiber (6.67 ± 0.33%), and carbohydrate (39.80 ± 0.15%). Potassium (1080.02 ± 32.51 mg/100g dry weight) was found as a major trace element among others (Na, Ca, and Iron). Overall seventeen amino acids were identified and the most abundant amino acid in red amaranth wasglutamic acid(23.61 ± 0.16 mg/g). However, lysine (14.32 ± 0.20 mg/g) was found to be higher than each of theessential amino acidsin red amaranth. The value of total phenolic content, totalflavonoidcontent, and totalantioxidant activityin the methanolic extract of red amaranth was 30.27 ± 1.98 mggallic acidequivalent/g, 16.75 ± 0.82 mgquercetinequivalent/g and 62.91 ± 3.35 mgascorbic acidequivalent/g extract respectively. The IC50value for DPPH radical scavenging activity was 730.93 μg/mL. The selected vegetable also contained an appreciable amount of carotenes (15.37 ± 0.27 mg/100g). Plant extract had a modest extent of bacterial growth inhibition activity. Thus, red amaranth is a wonderful source of nutrients, a natural antiradical, and has otherbioactive compoundsthat should be in a regular dietary item and useful for nutraceuticals.