This research was taken up to investigate the antioxidant activity of roots of Plumbago zeylanica. The in vitro antioxidant activity of ethanolic extract of roots of Plumbago zeylanica was investigated by DPPH free radical scavenging, nitric oxide scavenging and Superoxide scavenging methods at dose of 100–1000 μg mL–1. The ethanol extract showed good antioxidant activity in these above methods. The maximum activity was found in DPPH free radical scavenging model. The antioxidant activity was dose dependent.