In this study, raw and treated wastewaters were reused for potato cultivation in order to verify the effect of wastewater on crop yield, crop’s heavy metals’ concentration as well as some major traits of potato. To this regard, a completely randomized test was designed with five water treatments and three replications. The watering were as follows: raw wastewater (T1), treated wastewater (T2), a combination of 50 % raw wastewater and 50 % fresh water (T3), a combination of 50 % treated wastewater and 50 % fresh water (T4), and fresh water (T5). The experiments were run during October 2009–June 2010 in the greenhouse of Bu-Ali Sina University. The results show that the effects of treatments were significant on the length and number of stems per plant (p < 0.05). The number of nodes and weight of tubers, crop yield and heavy metal (cadmium, nickel and lead) concentration in shoots and tubers were also significant (p < 0.01). The results indicated that the highest length of stem (55.44 cm) was obtained in T2 which had no significant differences from that of T1. The maximum and minimum tuber weights and crop yield were obtained in T1 and T5, respectively. Based on crop yield rate, the watering ranked as follows: T1 > T3 > T2 > T4 > T5. The maximum and minimum heavy metal values were observed in T1 and T5, respectively. Based on the cadmium, nickel and lead accumulations in shoots and tubers (except cadmium in shoots), the watering treatments ranked as: T1 > T3 > T2 > T4 > T5.