The vascular relaxant and antihypertensive effects of newly developed salts of amlodipine-maleate and camsylate-were evaluated on isolated aorta from rats and in spontaneously hypertensive rats, and compared with those of amlodipine besylate, a standard drug. Amlodipine besylate concentration-dependently inhibited $Ca^{2＋}$-induced contraction in depolarised rat aorta($IC_{50}$/: 4.17 nM), with a very slow onset of action. Amlodipine maleate and amlodipine camsylate also showed vascular relaxant effect with a pattern and a potency similar to those of amlodipine besylate($IC_{50}$/: 3.62 and 3.28 nM, respectively). Amloclipine besylate produced a dose-dependent and long-lasting(>10∼24h) antihypertensive effect with a slow onset of action (ED$_{20}$: 2.31 mg/kg) in spontaneously hypertensive rats. Amlodipine maleate and amlodipine camsylate also exerted antihypertensive effects with a pattern and a potency similar to those of amlodipine besylate(ED$_{20}$: 2.09 and 2.21 mg/kg, respectively). These results suggest that amlodipine maleate and amlodipine camsylate are not statistically differ with amlodipine besylate in relaxant effect of $Ca^{2＋}$-induced contraction in depolarised rat aorta and in antihypertensive effect in spontaneously antihypertensive rats.