Beef steaks (192) from longissimus muscles, that differed widely in amount (degree), distribution and texture (size) of marbling were oven roasted at 121, 177 and 232°C to four final internal temperatures (60, 70, 80 and 90°C) to evaluate the effect of lipid composition on cooking properties. Interactions of oven temperature, internal temperature and carcass maturity, with marbling amount, distribution and texture were not significant. Cooking times were significantly affected by amount, distribution and texture of marbling, and were highest for steaks that were low in amount, uneven in distribution and coarse in texture of marbling. Degree of doneness did not differ significantly among the various groups for amount, distribution and texture of marbling.