This study was conducted in Bornova experimental fields of Department of Field Crops, Faculty of Agriculture, University of Ege, Turkey during 2015 and 2016, in order to determine the effects of treated sewage sludge on yield and quality of vetch + barley mixture. The experimental design was in Randomized Complete Block Design (RCBD) with four replications. In the trial, 10 t ha-1 , 20 t ha-1 and 30 t ha-1 treated sewage sludge were used in addition to the control and mineral fertilizer application and some characteristics such as plant height, botanical composition, fresh herbage yield, dry matter rate, dry matter yield, the rates of crude protein and crude ash, the yields of crude protein and crude ash, Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) rates were determined. The results showed that plant height, botanical composition, fresh herbage yield and dry matter yield were significantly affected by the applications. In the study which the highest vetch and barley plant height and dry matter yield were obtained with sewage sludge applications of 20 and 30 t ha-1 , the highest vetch rate in botanical composition was obtained with control and mineral fertilizer applications. Sewage sludge applications of 10, 20 and 30 t ha-1 gave the highest barley rate in botanical composition. Dry matter rate, crude ash rate and yield, crude protein rate and yield, NDF and ADF rates were not affected by mineral fertilizer and sewage sludge applications. When the results are evaluated in general, according to the soil analysis results and heavy metal amounts from the sewage sludge, it is concluded that 20 or 30 t ha-1 sewage sludge can be used in vetch + barley mixtures.