The aim of this research was to investigate the influence of muscle type on protein oxidation, texture profile (hardness, springiness, cohesiveness and chewiness) and proximate composition of beef from grain-finished Bos indicus (Nellore) cattle in Brazil. The muscles longissimus lumborum (LL) and psoas major (PM) were collected 24 h post mortem from eight (n=8) Nellore bull carcasses, fabricated into five steaks (1.5-cm) and displayed under aerobic conditions for nine days at 4 °C. Proximate composition and texture profile were analyzed on day 0, whereas protein oxidation was analyzed during 9 days of storage. LL exhibited greater (P<0.05) protein concentration than PM steaks, whereas PM demonstrated greater (P<0.05) lipid and ash content than their correlative LL. In addition, LL steaks exhibited greater (P<0.05) hardness, springiness, cohesiveness and chewiness than PM steaks. In contrast, protein oxidation was greater (P<0.05) in PM than in LL steaks throughout the storage. The results suggest that the differences of muscle metabolism and composition contributed to the variation on biochemical attributes and texture profile of LL and PM steaks. Muscle-specific strategies are indicated to improve the color stability of PM steaks from grain-finished Bos indicus cattle.