A study was conducted to evaluate early weaning of beef calves at 60-70 days of age on feedlot performance and carcass characteristics. One hundred twenty steer calves sired by either Simmental or Angus sires were weaned at an average age of 67 (early weaned, EW) or 147 (late weaned, LW) days. Calves were allotted to 16 feedlot pens by weaning treatment and sire breed at approximately 750-800 lb. EW calves were heavier (P < .05) in initial feedlot weight. There were no differences due to weaning age on daily gain, dry matter intake, feed efficiency or slaughter weights. Simmental steers required more days on feed than Angus steers (P < .05). Early-weaned calves had a higher percent intramuscular fat (5.7 vs. 5.1%), higher average marbling scores (Small78 vs. Small20, P < .05), a higher percentage of cattle grading average USDA Choice and higher (38% vs. 14%, P < .05) and a higher percentage of USDA Prime (10% vs. 0%, P < .05). These data confirm observations in previous studies that early weaning and placing calves on a higher grain diet improves marbling at slaughter. In this study, the effect was shown in calves weaned at an average of 67 days.