The aim of this work was to study the carcass killing-out proportions and carcass composition of Churra Galega Bragançana (CGB) and Suffolk sheep at 20%, 25%, 30% and 35% of maturity. Forty-eight male lambs were used, 24 CGB and 24 Suffolks from the Bragança's School of Agriculture sheep flock. Suffolk lambs had greater proportions of leg, shoulder and breast joints, but lower proportions of rib, anterior rib and neck joints. Increasing maturity caused a significant decrease in leg and shoulder proportions and an increase in chump proportion. Suffolk lambs had significantly greater muscle and significantly less subcutaneous fat and kidney and pelvic fat percentages than CGB lambs. With the increase of maturity, a significant increase in intermuscular fat and a significant decrease in bone proportion were observed. It was concluded that, under the management conditions of this work, Suffolks were preferred for meat production, since at a comparable stage of maturity they had greater proportions of expensive cuts and greater carcass lean percentage.