Aqueous extracts of roots of Boerhavia diffusa were evaluated for their CNS stimulant activity on mice . Mice were divided into five groups of six animals each. Group I was given normal saline and served as control. G roup II was given caffiene in the dose of 30mg/kg by oral route and served as standard. Group III, IV and V were g iven extracts of Boerhavia diffusa in lower, medium and higher do se i.e. 100, 200 and 400 mg/kg body weight by oral route respectively. After 60 min of oral administration, CNS activity of mice was evaluated using rota rod a nd actophotometer models. Motor coordination and locom otor activity was found to be increased in medium a nd high dose as compare to control group and were found to be comparable with standard group. The results sugg ested CNS stimulant activity of aqueous extract of Boerha via diffusa at medium and high dose.