The effects of 2 supplements on the performance of Nellore cattle in their post-weaning phase on a marandu-grass pasture during the dry season were evaluated. It was expected that differences would occur in the average daily gain (ADG), thereby modifying the carcass gain (CG) and carcass gain percent (CGP). The experiment was divided into 3 experimental periods (EP) with 35 d each (105 d), beginning in 08/2009. A total of 129 animals aged 8 ± 2 mo, with an initial BW of 204 ± 5.2 kg, were used in the experiment. The following supplements were tested: protein supplement (PS) (1 g·kg^–1 BW, low-moderate ADG rate) and protein energy supplement (PES) (5 g·kg^–1 BW, moderate-high ADG rate). Animals were weighed at the beginning and end of the EP (after 16 h deprivation) to determine the ADG. For the calculation of CG, the initial carcass weight was estimated through the equations obtained with 3 animals slaughtered at the onset. The CGP was calculated by dividing the carcass gain by the BW gain. The animals were allocated to a 48.2-ha pasture area (deferred in April 2009) divided into 18 paddocks (9 per treatment). The experimental design was completely randomized, with the paddock considered the experimental unit. To evaluate performance, 9 paddocks were considered per treatment (63 animals), while for the evaluations of carcass and body components, 3 animals were considered per treatment (6 animals); these results were subjected to ANOVA at 10% probability. Treatment PES provided a 44% higher ADG (P < 0.01) as compared with PS. The animals ADG was 0.72 kg (PES) and 0.50 kg (PS), resulting in a different BW at the end of the dry season (P < 0.01), which was 26 kg greater in the animals fed PES (285 kg) as compared with PS (259 kg). CG was not affected (P = 0.35) by the type of supplementation; however, the final carcass weight in the animals fed PES was 14.7% higher than in those which received PS (P = 0.05). The CGP (average 547.3 g carcass kg^–1 BW) was not affected (P = 0.94) by the supplements. Supplementation with PES increases the ADG and provides heavier carcasses.