Withania Somnifera (WS) is used as adaptogen, antiarthritic, antispasmodic, anti-inflammatory, nervine tonic, nerve soothing, antioxidant, immunomodulator, free radical scavenger, anti-stress and anti-cancer agent. But ergogenic value of WS as nutritional supplement is yet to be established. Objectives: Present study was designed to investigate the effect of supplementation of WS on the VO2max and Haemoglobin in Hockey Players. Method: Thirty two male hockey players, with a mean age of 17.4 ± 1.7 years and BMI 20.9 ± 2.9 kg/m2 volunteered for the study. Subjects were randomly assigned into two groups Group I (n=16): Withania somnifera group (experimental group) and Group II (n=16): Placebo (control) group. The experimental group received 500 mg capsules of aqueous roots of Ashwagandha twice daily for eight weeks, whereas the placebo group received starch capsules. Maximal oxygen consumption capacity in ml/kg/min (VO2max.) with Cooper (1968) 12 min. run test and hemoglobin (Hb) of both experimental and control groups were measured before and after the administration of Withania somnifera and placebo respectively. Results: A significant improvement in the VO2max (t = 2.98, p< 0.01) and hemoglobin (t = 2.78, p < 0.01) in experimental group was found. Whereas not any significant change in pretest and posttest values of VO2max and Hb was observed in the placebo group. Conclusion: Supplementation of Withania Somnifera improves VO2max and hemoglobin concentration in young hockey players.