Parkinson's disease is a neurodegenerative condition. In this disease nigro striatal dopaminergic pathway is demaged. In addition to dopaminergic neurons which predominantly are affected, some other neurotransmitter systems (i.e. serotonergic system) are also involved in pathophysiology of this disease. Hence, we studied the effect of sertraline, as a selective serotonin reuptake inhibitor, on catalepsy produced by unilateral infusion of 6- hydoxydopamine (6-OHDA) into the substantia nigra, compact part (SNc). Male wistar rats weighting 180-200g were used in the present study. In order to induce experimental parkinsonism, 6-OHDA (8 μg/rat) was infused unilaterally into the SNc of rats. 6-OHDA induced catalepsy (p<0.001) was evaluated by the aid of a bar test 5, 60, 120 and 180 minutes after intraperitoneal (i.p.) injections of the drugs. Sertraline (1 and 2 mg/kg i.p.) markedly attenuated the cataleptic behavior (P<0.001). This effect of sertraline is reversed by NAN-190 (0.5 mg/kg, i.p.) ( p<0.001). In conclusion sertraline possibly via activation of 5HT1A receptors is able to improve motor disorder in this model of Parkinson's disease.