the objective of this work was to evaluate weight gain and carcass characteristics nellore cattle, castrated or non-castrated, finished in confinement. it was used thirty six animals with 24 months old and initial 445.30 kg bw (non-castrated) or 449.57 kg bw (castrated at 400 kg bw). the animals were slaughtered at 50 days of confinement, when reached 516.30 kg bw (non-castrated) and 506.86 kg bw (castrated). non-castrated animals did not have an increase in final bw, but showed higher weight gain (1.42 and 1.15 kg). hot carcass weight (272.77 and 261.89 kg) and cold carcass weight (266.13 and 258.24 kg) did not differ between non-castrated and castrated animals. non-castrated animals showed higher hot carcass yield (52.88 vs. 51.65%) however, cold carcass yield was similar between groups (51.55 and 52.39%), due to smaller chilling loss in castrated animals (2.43 vs. 1.40%). special hindquarter absolute weights (133.07 and 131.55 kg), forequarter (105.65 and 100.09 kg) and spare ribs (27.41 and 26.60 kg) did not differ between non-castrated and castrated animals. forequarter relative values castrated animals were higher than the non-castrated (50.93 versus 50.00%). the striploin of non-castrated animals was heavier than that of castrated (8.41 vs. 7.90 kg). fat thickness (2.05 vs. 2.21 mm) and loin eye area (66.98 versus 67.48 cm2) did not differ between non-castrated and castrated animals. cold carcass ph in predetermined time until setting of rigor mortis is also similar between and non-castrated and castrated animals. non-castrated and castrated animals have satisfactory carcass weight, but have not fat thickness less than 3 mm, when confined for 50 days with diet based on sugar cane and concentrate. to match the fat thickness, the diet of the animals must be balanced with higher energy level.