Myrtus nivellei Batt and Trab. is a Sahara-endemic plant belonging to the Myrtaceae family, this plant is very famous in southern Algeria for its therapeutic properties in folk medicine. However, its uses are limited exclusively to the ancestral know-how. In the present work, three extracts were prepared from the leaves of this plant: an ethanolic extract, a methanolic extract and an aqueous extract. The yields of dry crude extracts are respectively 11.12%, 12.45% and 16.5%. The quantitative estimation of flavonoids, flavonols and total phenols by the spectophotometric method showed that the three extracts contain these compounds. The evaluation of antioxidant capacity by the method of free radical scavenging test showed that all of the extracts have a very good reductive activity, especially for ethanolic extract which presented a percentage of inhibition equal to 78.81% with an EC50 estimated to 0.59 mg/ml. On the other hand, the FRAP test revealed that the methanolic extract has the best reducing power (66.71%) than those of the other extracts, but it remains relatively low compared to the ascorbic acid used as positive control.