Water is a major environmental constraint for agricultural practices in developing countries. As a result of lack of water storage, infrastructure, large spatial and temporal variations in rain fall and less or no availabilityof enough water farmers do not produce more than one crop per year.To relive from such constraints irrigation schemes are commonly used, but lack of sufficient and effective irrigation in agriculture contributes to low agriculture yields. Recently, Ethiopian government starts to construct irrigation schemes, as irrigation increases the yieldof cultivated land, allowsgreater productivityand improve Ethiopian economy. Among irrigation schemes under construction Ribb dam is one in south Gonder Zone at Ebenat district. Thus the main objective of this study was assessing the irrigation Water quality of Ribb dam by analyzing the physicochemical parameters like pH, TDS ,EC, TH(total hardness) PO ,NO 3 - ,Cl - , and metals Pb, Mg ,Ca, Zn and Cd. Those parameters were analyzed in four sampling site of the study area with dry and wet season by using ICP-OES, Flame Photometer and multimeter (pH meter, conductometer). The result of physicochemical parameter during dry and wet season the minimum and maximum valuewasobtainedpH(7.32,7.53),TDS(54.8mg/L,129.9mg/L),EC(108.3µs/cm,271.3µs/cm),TH(56. 62mg/L,73.3mg/L),Cl - (0.6mg/L,8.93mg/L),NO 3 - (1.2mg/L,3.93mg/L),SO4 -2 4 3- (1mg/L,4.3mg/L),PO (0.19mg/L,1.35mg/L)respectively.AndmetalsCa(1.99mg/L,2.99mg/L),Mg(0.373mg/L,0.66mg/L),Z (0.0142mg/L,0.187mg/L).These studies confirm that value of most parameter were found under permissible limit of WHO, but Pd and Cd were not detected. Key words: irrigation, water quality, Ribb dam, physicochemical properties, and ICP-OES. ,SO 4 2- 4 -3