Effects of polyethylene mulch, planting pattern and irrigation intervals on growth and yield of potato cv. Agria were investigated in 2001. The experiment was carried out as a split plot in a complete randomized block design with three replications, irrigation intervals as main plots (7 and 14 d), planting pattern (common and zigzag) as sub-plots, and mulch (black, transparent polyethylene and bare ground) as sub–sub plots. Weekly irrigation intervals increased main stem diameters, plant fresh and dry weight, main stem number, plant height, tuber weight per plant and yield, but decreased the percent of total soluble salts, very small and small tubers percentages and had no effect on the other traits. Common planting pattern increased only tuber weight per plant. Black and transparent polyethylene mulches increased main stem diameter, plant height, yield, plant fresh and dry weight, tuber weight per plant and the percent of medium and big tubers but decreased the percent of very small and small tubers. Interactions between irrigation intervals and planting pattern on tuber weight per plant were significant. Interactions between irrigation intervals and mulch on plant fresh and dry weight, main stems number yield and tuber weight per plant were significant. Also interaction between planting pattern and mulch had significant effects on tuber weight per plants. The results of this study demonstrate that the black polyethylene mulch, common planting pattern and weekly irrigation intervals were the best treatments.