Vietnamese ginseng (Panax vietnamensis Ha et Grushv., Araliaceae) is a valuable medicinal plant of Vietnam. Pharmacological studies have been carried out on wild Vietnamese ginseng and revealed remarkable activities of including antifatigue, anti-stress, anti-depression, antioxidation, hepatoprotection, etc. However, in recent years, Vietnamese ginseng is mostly obtained from cultivated plants, as the wild ones become increasingly scarce. The aim of this study is to evaluate the effect of6-year-old cultivated Vietnamese ginseng on endurance swimming capacity in mice. Brekhman's swimming test and current-adjustable pool model were applied in mice to investigate the effect of Vietnamese ginseng extract after oral administration of single dose or repeated doses for 7 days or 14 days at doses of 10 mglkg, 50 mglkg, and 100 mglkg. An extract of six-year-old cultivated Panax ginseng was used as a reference control. The result showed that both Vietnamese ginseng extract and Panax ginseng extract at doses of 10, 50, 100mg/kg significantly prolonged the swimming time in both tests as compared to control group. Especially, treatment with Vietnamese ginseng extract at 'dose of 50mglkg for 7 consecutive days showed a significant increase (60 percent) in percentage of swimming time compared to Panax ginseng extract 50 mg/kg (p0,05) in Brekhman's swimming test.