Chlorella is a genus of green microalgae which produces high biomass, presenting higher photosynthetic efficiency when compared with other microalgae. The objective of this study was to analyze the protein content and antioxidant activity of Chlorella sp. Chlorella has important uses in bioindustry and biopharmaceuticals. Biosynthesis of bioactive metabolites is also important for industrial uses. To combat issues associated with its inherent low growth rate, chlorella can be genetically transformed to produce more biomass. For this reason, bioproducts from microalgae are in demand and high value. In our experiment, we used BG11 media to culture microalgae and assessed its protein content and antioxidant activity. Microalgae cultures were first obtained from colonies on plates with BG11 solid media. Clones were then cultivated and grown in BG11 liquid media. Once these cultures reached the stationary phase, biomass was extracted by aqueous abstract, methanolic abstract, and ethanolic extract. Bicinchoninic Acid (BCA) method was used to analyze protein content. The antioxidant activity was then calculated using (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) method. BCA method and ABTS method results indicate that Chlorella sp. is the ideal candidate for biomass production and monitoring antioxidant activity.