Abstract: This study was carried out to investigate the effect of treated wastewater on yield quantitative and qualitative properties in fresh forage of sorghum. The experiment was conducted at the University of Zabol in Iran during 2007 growing season by using a randomized complete block design and four replications. The treatments were managed for irrigation; with well water during entire period of growing season as control (T1); well water during entire period of growing season along with NPK (T2); wastewater during the first half of growing season (T3); wastewater during the second half of growing season (T4); wastewater and well water alternately (T5) and wastewater during entire period of growing season (T6). Results showed irrigation with wastewater lead to significant increase (p≤0.01) on total yield, leaf fresh and dry weight, stem fresh and dry weight, stem diameter and leaf number in plant based on Duncan test for comparing, maximum yield (13 ton ha-1) was obtained by irrigation with wastewater and well water alternately, also significant increase in forage qualitative indexes such as WSC, CP, ASH and significant decrease in NDF and ADF. Irrigation with wastewater and well water alternately has shown lower NDF, ADF and favorite CP in comparison with usage of wastewater during the whole growth period.