The use of restricted grain supplementation effects on animal performance, carcass weight, meat quality traits and fatty acids profile of intramuscular fat was researched on finnishing steers under grazing conditions. The experiment lasted for 150 days, from 11th June to 9th December 2007, where twenty four Uruguayan Hereford steers were assigned to different treatments (T) considering herbage allowance (HA) on pasture (P) and grain (ground sorghum) supplementation (G) according to the liveweight (LW) of the animals. The treatments applied were a combination of P allowances and unique G supplementation level, being T1 (P at 4% HA of LW); T2 (P at 2% HA of LW without G) and T3 (P at 2% HA of LW + G at 0.8% of LW). The increase in HA and G increased animal performance, ribeye area, carcass weight and fatness, and pistola cuts and had limited influences on meat quality traits (marbling, pH, meat colour, tenderness). Intramuscular fat was affected by T (T3>T1>T2; PT3; PT1=T3 (PT1>T3 (PT1>T3; PT1=T2 (P