The objective of this study was to examine the relationship of feedlot performance, DMI variation and rumen morphometrics of Nellore cattle classified by residual feed intake (RFI). A study was conducted, in 2 consecutive years, using individual pens at São Paulo State University feedlot, Dracena campus, Brazil. At year 1, forty-eight 20-mo-old Nellore bulls (358.2 ± 19.4 kg) were fed for 94 d. At year 2, sixty 20-mo-old Nellore bulls (402.5 ± 33.0 kg) were fed for 84-d. All Nellore bulls were categorized as high RFI (RFI >0.5 SD above the mean, n = 25), medium RFI (RFI ± 0.5 SD from the mean, n = 56) and low RFI (RFI <0.5 SD below the mean, n = 27). The finishing diet, in both years, contained: 71.5% cracked corn grain, 16.0% sugarcane bagasse, 7.7% soybean meal, 3.5% supplement, and 1.3% urea (DM basis). Variables were analyzed by a linear model with year and RFI groups as the main effects, with interactions. Animals classified as low RFI had lower (P = 0.01) initial BW (high = 382.5 kg; medium = 378.1 kg; low = 371.8 kg), daily DMI in kg (high = 10.1 kg; medium = 9.5 kg; low = 8.2 kg), daily DMI expressed as % of BW (high = 2.32%; medium = 2.18%; low = 1.92%), and improved (P = 0.01) G:F ratio (high = 0.112; medium = 0.131; low = 0.143). However, no significant (P > 0.10) RFI effect was observed for ADG (high = 1.14 kg; medium = 1.25 kg; low = 1.16 kg), final BW (high = 484.0 kg; medium = 489.5 kg; low = 474.7 kg) and HCW (high = 266.7 kg; medium = 262.7 kg; low = 256.1 kg). Moreover, animals categorized as high RFI had lower (P = 0.02) DMI variation (high = 12.28%; medium = 15.14%; low = 16.24%). No significant (P > 0.10) RFI effect was observed for rumenitis (high = 1.4; medium 1.4; low = 1.1), number of papillae (high = 45.6; medium = 43.6; low = 43.1), and absorptive surface area (high = 25.4 cm²; medium = 26.3 cm²; low = 22.7 cm²). Nonetheless, Nellore bulls ranked as low RFI presented smaller (P = 0.07) mean papillae area (high = 0.55 cm²; medium = 0.60 cm²; low = 0.50 cm²). Selection of low RFI Nellore bulls is feasible because it does not negatively affect feedlot performance, HCW, and rumen characteristics.