This study was carried out to evaluate the nutritional value of different levels of unprocessed or processed common vetch seeds (CVS) for use in broiler diets. A total of 420 broiler chicks (Ross 308) were used in a completely randomized design from 22 to 42 d of age. The experimental diets were a corn-soybean meal positive control, 3 inclusion levels of CVS (100, 200, and 300 g/kg), and 2 processing treatments (unprocessed and processed). No difference in feed intake was observed between the different experimental treatments. Increasing the CVS level in the diet significantly (P < 0.05) decreased BW gain and increased FCR. The processing method used in this study significantly (P < 0.05) improved BW gain and FCR. When the positive control treatment was compared with the other treatments, the inclusion of 300 g/kg of unprocessed or processed CVS and 200 g/kg of unprocessed CVS in broiler diets decreased BW gain and increased FCR compared with birds fed the control diet. Feeding different levels of CVS and using the present processing method did not have a significant effect on serum parameters, carcass characteristics, or small intestinal morphology. Inclusion of 300 g/kg of unprocessed CVS in the diet resulted in lower abdominal fat and higher liver relative weights when compared with those of the control birds. In conclusion, unprocessed CVS can be used at up to 100 g/kg in grower diets of broiler chickens, and the processing method used in this study could improve the nutritional efficiency of CVS because the productive performance of birds fed 200 g/kg of processed CVS was similar to that of control birds.