Prostaglandin F2 alpha is one of the most important stimulators of myometrial contractility. The effect of a adrenoreceptor antagonist (hgdergine) and calcium channel blocker (verapamil) on prostaglandin F2 alpha induced myometrial contractions were studied. This study was carried out on isolated uteri from non pregnant albino rats in oestrous stage. Alpha adrenoreceptor antagonist (hydergine) at different concentrations (120,240 and 300 ug/bath) caused a concentration dependant inhibition of myometrial contraction induced by prostaglandin F2 alpha giving a possibility of alpha mediated action. Calcium channel blocker (verapamil) at different concentrations (5,10and 20 ug/ bath), also, caused a concentration related inhibition of prostaglandin F2 alpha induced myometrial contraction giving evidevce that prostaglandin F2 alpha promote trans-membrane calcium influx through receptor operated calcium channels.