Antioxidants may be of great benefit in improving the quality of life by preventing or postponing the onset of degenerative diseases. In addition, they have a potential for substantial savings in the cost of health care delivery. Various methods are used to investigate the antioxidant property of samples. Antioxidant activity of Commelina maculata leaves and AgNPs were carried out for proving its utility in free radical mediated diseases. The leaves extract and AgNPs were screened for in vitro antioxidant activity by oxygen radical scavenging such as DPPH, total antioxidant assay, superoxide radical scavenging, iron chelating and reducing power activity at different concentrations. The antioxidant activity was found to be concentration dependent. Among this AgNPs possess potential antioxidant activity as compared with plant extract and close to the standard.