PEMFC feed gases need to be humidified before entering the fuel cell to avoid membrane dehydration. However, the gas saturator temperature must be considered relative to the cell temperature, otherwise, flooding may occur if too much water is promoted to the cell. This study investigated the effects of relative humidity of reactant gases streams. The humidifier temperatures of 75°c, 90°c and 95°c were studies in relations to the cell temperature of 80°c. The results show that the humidifier temperature of 75 °c performed the best whereas the worst performance was obtained when the humidifier was operated at 95°c. It was found that the effect of water product is less at low current density because the chemical reaction is less. However, at high current density, the cell performances at the saturator temperatures of 90°c and 95°c drop due to move water production leading to flooding. Operating fuel cell below the dew point of the reactant gas streams, the water from the reactant is partially condensed when it enters the cell. The excessive liquid water from reactant gases coupled with more water produced from chemical reactions thus blocks the pore network of anode/cathode GDLs. Therefore, flooding results in the high current region which leads to mass transport losses and poor cell performance