ABSTRACT Rilmenidine is proposed as a selective imidazoline receptor rather than (2 adrcnoreceptor drug. It was reported that rilmenidine causes marked centrally-mediated hypotension, whilst the incidence of its adverse effects is quite low. Clonidine is an¬other centrally acting antihypertensive agent characterized by its wide therapeutic range. The mechanism of its antihyperten¬sive action appears to be through stimulation of postsynaptic (2-adrenergic receptors in the nucleus tractus solitari of the me¬dulla oblongata. The present study aimed to investigate: (1) The antihypertensive effect of rilmenidine 1mg/kg i.v versus that of clonidine 0.03mk/kg i.v in experimentally induced-hypertension in rats by renal artery occlusion. (2) Study the possible sedative effect of rilmenidine l0mg/kg i.p versus that of clonidine 0.25mg/kg i.p. (3) Evaluate the effect of yohimbine 10mg/kg i.v on rilmenidine and clonidine actions. The results of the present study revealed that at equipotent doses; both rilmenidine &. clonidine induced a transient signifi¬cant (p0.05) effect on sleeping time induced by pentobarbitone 30 mg/kg i.p, whilst clonidine produced significant (p