The volatile compounds in cooked beef from the local Spanish cattle breeds, Asturiana, Avileña, Parda Alpina, Pirenaica, Retinta, Rubia Gallega, and Morucha, were studied. Bulls were slaughtered at a live weight of 300 and 550kg and the beef was aged for seven days before cooking. Differences in volatile composition among the breeds were considerable and may contribute to the perception of flavour differences in the cooked beef. Peak area values for dimethyl sulfide, which could be related to cauliflower notes, were highest for the meat from the Pirenaica breed. Levels of the detected volatiles, especially sulfur compounds, in the beef from the Asturiana breed were low-intermediate and were potentially related to blood and liver notes and unpleasant flavours. Avileña stood out among the rustic breeds because of its high values for 1-octene, methylcyclohexane, tetradecane and carbon disulfide, while Retinta displayed high 2,3,4-trimethylpentane levels. The effect of weight at slaughter was influenced by breed, because, except for octane, all the volatile compounds behaved differently according to the breed. Ethanol was characteristic of animals with a high percentage intramuscular fat content, and carbon disulfide was characteristic of animals slaughtered at the lower of the two live weights considered.