Pig-breeding businesses have resulted in global breeding programs that select pigs to perform well on high-energy high-protein diets, which are traditionally based on corn and soybean meal. Nowadays, there is a shift toward diets based on cereals and co-products, therefore, high dietary inclusion of co-products can modify the expected performance of these pigs. The objective of this study was to evaluate the effect of feeding a cereals-alternative ingredients diet (CA-diet) compared to a corn-soybean meal diet (CS-diet) on the growth performance, feed efficiency, and carcass characteristics of genetically similar growing-finishing gilts and boars. In total, 160 pigs, 80 gilts and 80 boars, coming from 18 litters were used. The pigs were blocked based on litter, to ensure no genetic differences between the 2 treatments. For the starter phase, pigs fed the CA-diet performed in terms of growth, and feed efficiency, as good as the pigs fed CS-diet (P > 0.05). For the grower phase, pigs fed the CA-diet had the same ADFI (P > 0.05), but a lower daily energy intake (ADEI) (P < 0.001), and same growth performance (P > 0.05) than pig fed the CS-diet, therefore pigs fed the CA-diet were more efficient in terms of residual energy intake (REI) (P < 0.001). For the finisher phase, interaction between diet and sex had an effect on ADFI (P < 0.001), ADEI (P < 0.001), ADG (P = 0.010), and lipid deposition (Ld) (P = 0.016). Pigs fed the CA-diet were less efficient than pigs fed the CS-diet, i.e., G:F (P < 0.001), RFI (P < 0.001), and REI (P = 0.007). In general, feeding a CA-diet to pigs showed to improve the ratio between Pd and Ld, especially for boars. Also, pigs fed the CA-diet showed thinner back fat thickness (P < 0.001), same loin depth thickness (P > 0.05), but lower dressing percentage (P < 0.001), than pigs fed the CS-diet.