Abstract: Background and Objective: In cultivation of crops at medium plains which have a high temperature, the use of shade not only decreases the light intensity but also decreases the temperature and maintains the soil moisture in order to create suitable conditions for the growth of potatoes. Accordingly, the use of both shade and suitable interval of watering on potatoes cultivated at medium plains is expected to increase the yield. The objective of this study was to determine the effect of shade and water interval on plant growth. Materials and Methods: Experimental design used in this research was split- plot design with including some factors, namely, main-plot factor consisted of 2 levels of shading net (without and with), sub-plot factor consisted of 4 levels of watering interval (1, 2, 3 and 4 days). All parameters were tested by two ways of analysis of variance (ANOVA) by Fisher test followed by Duncan’s Multiple Range Test at the 5% significance level. Results: The results showed that there was efficiency on potato yield cultivated in medium plains by watering with the application shade. In shade treated plants the highest yield is obtained at interval watering every 2 day. In treatment with shade, the highest yield was obtained at watering every 3 days, whereas in without shade plants, the highest yield was obtained at watering every 2 days. Conclusion: It would be concluded that the use of shade on Atlantic cultivars potatoes can increase the efficiency of water use so that watering can be done once every 3 days.