Aim: The experiment was carried out to evaluate the effects of supplementing different levels of protein and energy sources on blood biochemical profiles of Brahman crossbred cattle. Materials and Methods: The study consisted of two experiments in Brahman crossbred cattle in An Giang Province. In trial 1, 28 cattle of 178±12.5 kg were arranged in a completely randomized block design. In the second trial, another 24 cattle of 182±14.3 kg were allocated in a 2 × 3 factorial design. The experiments lasted for 90 days. Blood samples were taken at the end of the experiments, and plasma concentrations of metabolites and enzymes were analyzed by an automated biochemical analyzer (Humalyzer 3000, USA). Results: The glucose concentration was highest at 1.83 mmol/L when supplemented with urea (60 g/head/d). Urea and creatinine content was not significantly different between treatments when cattle were supplemented with different protein and energy sources. In the treatment with 360 g/head/d soybean meal supplementation, cholesterol concentration was lowest (2.50 mmol/L), compared with the highest concentration (3.86 mmol/L) in the treatment with soybean meal at 720 g/head/day. The total protein concentration showed the highest values at 94.5 g/L and 96.3 g/L when supplemented with soybean meal (720 g/head/day) and fish oil, respectively. Conclusion: There were slightly altered blood biochemical profiles among cattle at different protein and energy source supplements.