The aim of the present study was to evaluate the effects of feeding faba bean and sweet lupin as alternative protein sources to soybean on productive performance, blood parameters, carcass composition, and chemical-physical characteristics of meat and its fatty acid (FA) profile in Charolais heifers. Twenty-four heifers were divided into three homogenous groups and fed with durum wheat straw and three iso-energetic and isonitrogenous pelleted complete diets containing 14% (on as-fed basis) soybean meal; 28% faba bean; and 20% sweet lupin seed. The animals were slaughtered after a 168 day feeding period, and the Longissimus lumborum muscle was sampled for meat quality measurements. The feed conversion index was better in the heifers fed faba bean compared with the soybean treatment group (6.71 versus 7.17). No differences were found among treatment groups in productive performance, slaughtering data and physical features. The concentration of linoleic acid in the meat of the soybean group differed significantly from that in the lupin group (2.38 versus 2.11%). Feeding lupin seed increased the concentrations of C20:3 n-6 (0.09%) and C20:4 n-6 (0.20%) in meat significantly, compared with the soya- and faba bean treatments (0.06–0.07% and 0.12–0.13%, respectively). No differences were found among groups for blood parameters, except for urea concentration, which was lower in the lupin group compared with the concentrations in the serum of heifers receiving the soya bean treatment (31.29 as opposed to 37.56 mg/dL). In conclusion, since faba bean and lupin seed did not affect any of the parameters negatively, these legume grains can be included successfully as alternative protein sources in beef cattle diet.