The aim of this study was to determine blood lactate concentration during the feedlot (FE) period and after slaughter and to check its influence on body weight and meat quality traits in Nellore cattle finished at feedlot. Ninety uncastrated males were submitted to the feedlot. Animals had average weight of 390 ± 37 kg and about 24 months of age. Lactate measurements was measured by spectrophotometry on the day 1 (L1), day 14 (L14), day 27 (L27), day 69 (L69) and day 96 (L96). Muscle meat samples were collected from Longissimus thoracis and laboratory analysis of lightness (L*), redness color intensity (a*) and yellowness (b*), shear force (SF) and pH of meat samples without aged (_0) and aged for seven days (_7) were performed. The lactate variables were analyzed by least squares with the use of PROC MIXED of SAS, considering a model with effects of pen and day of blood sample collection. Analysis of body weight at day 69 (W69) and meat quality traits were performed with a model including pen and lactate effects. Phenotypic correlations (r²) were performed. Lactate remained stable during the FE period with means of 4.83±0.30 mMol/L, 5.68±0.29 mMol/L, 5.03±0.29 mMol/L and 4.15±0.31 mMol/L for L1, L14, L21 and L69, respectively. Higher mean was obtained for L96 (10.77±0.27 mMol/L) compared with the previous four times (P<0.001). No significant association for W69 and L69 was found. For meat quality traits, the lactate effect was significant for a* and b* (P<0.10) just for _0. The r² estimated for lactate and a* of _0 was negative, 𝜌 = -0.19 (P<0.10). For lactate, r² was statistically significant just for measures performed during the FE period (P<0.05). The results of this study showed that the lactate measured during the FE period was stable and had no relation to the measurement made after slaughter and also the lactate at post slaughter can influence a* and b* in _0. It is important to avoid stress factors at this stage to ensure better color of the meat product.