The aim of the present study is to investigate the impact of the protein source and amylase addition and the interaction between these two on growth performance and nutrient utilization in particular starch digestibility and AMEN value in broiler chickens. A total of 960 one-day-old male broiler chickens (Ross 308) were utilized in this study. The chickens were randomly classified into four experimental groups, with each group having 30 replications, with eight birds per replication. The groups differed from each other with respect to the source of crude protein in diets (pea or faba bean seeds) and the addition of exogenous amylase (not added or added). The chickens had unlimited access to feed and fresh water and were kept under stable environmental conditions. The body weight and feed intake of the chickens were measured on the 14th and 35th days, with the aim of determining growth performance parameters. At the end of the study, the chickens were sacrificed and samples (excreta and digesta) were collected to estimate the nutritional value. The results showed no interaction (P > 0.05) between the protein source and enzyme addition in any of the analyzed growth performance and nutritional value parameters. The addition of amylase resulted in a higher body weight gain (0–35 days) and feed conversion ratio (each period). Moreover, significantly higher (P < 0.05) dry matter, starch, and amino acid digestibility were observed. Amylase addition resulted in lower excretion of total sialic acids (P < 0.05). The faba bean diet improved the growth performance and had greater nutritional value. In conclusion, amylase addition improved the growth performance and starch and amino acid digestibility. Therefore, it seems that the use of exogenous amylase is effective regardless of the source of protein in broiler chicken nutrition.