Parkinson’s disease (PD) is neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons in the substantia nigra pars compacta which innervates the dorsal striatum. Using haloperidol induced catalepsy in rat and muscle rigidity in mice effects of aq. extract of Ocimum sanctum (OSEaq) were studied. Haloperidol was administered to induce either short term model (0.5mg/kg i.p) or long term model (4mg/kg s.c.) to observe changes in catalepsy and muscle rigidity as measured using rota-rod test and chimney test. Out of 100mg, 200mg, 300mg and 600mg/kg p.o, doses of O. sanctum, 300mg/kg dose showed maximum shortening of onset and duration of catalepsy as compared with other dose levels in short term and long term model. Pretreatment with OSEaq (300mg and 450mg/kg p.o.) significantly reduces initial decrease in activity in rota rod and significantly improves performance of mice in chimney test as compared with control in short term and long term models. In conclusion, OSEaq in the dose 300mg/kg i.p. shows anticataleptic action in rats as well as in the dose 300 and 450mg/kg i.p. improves the performance of mice in rota-rod and chimney test indicating reduction of muscle rigidity. Active constituent-linalool, modulation of central neurotransmission might be responsible for the antiparkinsonian activity exhibited by OSEaq