Ligularia fischeri (LF) has been used to treat jaundice, scarlet-fever, rheumatoidal arthritis, and hepatic diseases. This study was carried out to determine the antioxidant activity of the extract from the leaves of LF by using various established in vitro systems with ${alpha}$-tocopherol as positive control. The results showed that the ethanol extract of LF (0.05-0.5 mg/mL) displayed a strong free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl, ${O_2}^{{cdot}-}$, and $H_2O_2$ radicals. It was observed that LF extract (1 mg/mL) significantly decreased the levels of malondialdehyde (MDA) to 69 and 89% of control, measured by ferric thiocyanate (FTC) and thiobarbituric acid (TBA) test, respectively. LF extract (0.5-2 mg/mL) was also found to inhibit significantly the amount of malondialdehyde formed from liver homogenate to 69-56% of control. Similarly, in the high $Fe^{2+}/ascorbate$ induction system LF extract (1-2 mg/mL) inhibited carbonyl formation measured by 2,4-dinitrophenylhydrazine reaction to 89-79% of control. Like antioxidant activity, the reducing power of LF extract was excellent at concentration of 0.5-2 mg/mL. These results indicate that LF could be used as a potential source of natural antioxidant.