Two RCD factorial experiments were carried out to evaluate the ability of two aquatic plants including watercress and pennyroyal to biosorption of lead and cadmium from polluted water in hydroponic conditions. First factor was plant species (watercress and pennyroyal) and second factor was consist of lead (50, 100, 150 mg/L) and cadmium (3, 6, 9 mg/L) in first and second experiment respectively. Root and shoot of both plants dried in an electric oven at 48hrs and 50 ○C after 14 days. 0.2 gr of plant powdered samples used for assessment of lead and cadmium accumulation by atomic absorption The highest lead accumulation in roots of pennyroyal and watercress was obtained by concentrations of 150 and 100 mg/L in (185348 and 3261 mg/kg dry weight respectively). The highest lead accumulation in pennyroyal and watercress shoots was 295.5 and 201.5 mg/kg respectively. Low translocation factors in both plants (lead 0.06 and 0.002 respectively and cadmium 0.4 and 0.004 respectively) mean less transport of metal to shoots and more accumulation of them in root consequently. There is a privilege characteristic because harvest of aquatic plants and root/shoot separation is easy.