Land application of wastes and recycling nutrients through the soil-plant complex has been a commonly accepted method of disposal. To study the effects of sewage sludge on wheat chemical composition and yield, in the field plot that includes treatments control, 25, 50 and 100 tons of sludge per hectare (based on dry weight) the wheat (Back-cross Roshan cv) was cultivated. Statistical design was a randomized complete block design with three replications. Sludge treatment significantly increased the wheat biomass, 1000grain weight and grain yield. Sewage sludge contains organic matter and nutrients required by the plant, and by affecting the chemical, physical and biological soil properties, can increase crop yield. The use of more than 25 tons’ sludge per hectare even in successive cultures is not recommended. Applying sludge caused significant increase the mean values of N and Fe in the wheat seed. Seed Cr, Co, Pb and Cd weren't in limit of atomic absorption system detection (µg kg-1).