The current study assessed antioxidants contents (total phenolics and total flavanoids, β-carotene and lycopene) present in Chlorella vulgaris (C. vulgaris) cultivated in low cost media and their free radical scavenging activities. Microalgae was cultured using Bold basal medium (BBM) as a control, 5% banana stem compost (BCM) and aquaculture wastewater supplemented with 1.0 g/L NPK (ANM). The free radical scavenging ability was analysed using 1,1-diphenyl-2-picrylhydrazyl assay. Cells grown on BCM resulted in higher (13.73 ± 0.121%) extraction yield than in other media. The phenolic (8.53 ± 0.10 mg/g GAE) and lycopene (0.29 ± 0.008 mg/g) content were highest in cells grown on BCM and BBM, respectively. Microalgae cultured in ANM displayed higher (547.023 ± 34.703 mg/g RE) flavanoid and β-carotene (2.887 ± 0.121 mg/g) content than in other media. Furthermore, cells cultivated in BCM showed highest (97.87 ± 0.088%) scavenging activity than in BBM. These results indicated that the BCM and ANM can be used as alternative to expensive synthetic media for antioxidant production in C. vulgaris.Sida Sweden under the Marine Science Bilateral Programme