The objective of the present investigation was to evaluate the therapeutic efficacy of Silymarin in DOCA salt induced hypertension in unilateral nephrectomized rats. Unilateral nephrectomy was performed in female Wistar rats (150-200 g). A week after unilateral nephrectomy, hypertension was induced by DOCA (25 mg/kg, once a week; s.c; for 4 weeks) dispersed in cottonseed oil. The effect of Silymarin (300 mg/kg and 500 mg/kg, p. o., for 4 weeks) was evaluated in DOCA salt induced hypertensive rats. Systolic blood pressure (BP) was measured once every week during the treatment schedule. After completion of treatment schedule, heart rate, arterial blood pressure and vascular reactivity to various drugs were recorded. Rats from individual group were sacrificed, the heart was dissected out and antioxidant enzyme level SOD, CAT, GSH and TBARS were measured. Urine excretions were measured by flame photometer. Silymarin (300, 500 mg/kg/day, p.o.) significantly ($p$ <0.05) reduced systolic blood pressure, heart rate, basal arterial blood pressure and pressor responses to NA, Adr, PE and 5-HT in animals treated with DOCA salt as compared with DOCA-salt hypertensive rats. Silymarin significantly increased antioxidant enzyme level of SOD, CAT, GSH, urinary $Na^+$ excretion and decreased TBARS level, urinary $K^+$ excretion compared with DOCA hypertensive group. Silymarin exhibits significant antihypertensive activity in DOCA salt model of hypertension.