Algae are highly significant in various fields due to their capability to replace chemical treatments and avoid their associated side effects. They have consistently shown strong efficacy against numerous diseases, regardless of whether they are micro or macroalgae. This research investigated the antioxidant and anticancer properties of a methanol extract from Chlorella vulgaris. The growth metrics revealed that C. vulgaris reached its peak optical density on the 8th day, its highest growth rate on the 18th day, and its maximum pigment content on the 12th day. The methanol extract displayed in vitro anticancer potential by inhibiting the proliferation of breast cancer (MCF-7) and colon cancer (HCT-116) cell lines, with a stronger effect against colon cancer, achieving inhibition rates of 80.57 ±0.81% and 76.43 ±0.74%, and IC50 values of 14.8 ±0.39 µg and 21.7 ±0.09 µg respectively. The extract's antioxidant activity was highlighted through DPPH and FRAP assays, showing the highest scavenging activity at a concentration of 5 mg/ml. Phytochemical screening identified phenols, alkaloids, flavonoids, glycosides, and saponins as active compounds. In conclusion, the methanol extract of C. vulgaris exhibited strong antioxidant and anticancer properties.