Abrus precatorius Linn (Fabaceae) is a climbing shrub; leaves are pinnate with many pairs of leaflets. Leaves 5-10 cm long, leaflets 10-20 pairs, opposite, flowers are pink clustered. The roots, stems, and leaves contain glycyrrhizin, sweet in taste. Leaves are traditionally have been used in the treatment of fever, asthma and caries of teeth. Clonidine induces catalepsy by releasing histamine from mast cells which is responsible for different asthmatic conditions. The leaves of A. precatorius traditionally used for asthma, hence objective of present study was to evaluate antihistaminic activity of A. precatorius using clonidine induced catalepsy in mice. In present study ethanol extract of A. precatorius leaves (EAPL) at doses 100, 125, 150 mg/kg i.p were evaluated for antihistaminic activity using clonidine and haloperidol induced catalepsy in mice. Finding of investigation showed that chlorpheniramine maleate (CPM) and EAPL inhibit clonidine induced catalepsy significantly P<0.001 when compare to control group, while CPM fail to inhibit haloperidol induced catalepsy. Present study concludes that EAPL possesses antihistaminic activity.