the accuracy of the methodologies: unesp-grade, grade, geometric, compared to autocad, in determining of the area rib eye-aol was studied. forty santa inês intact male lambs with different body weights were used. left half carcasses were conducted a cross-sectional at the level of 13th rib and the first lumbar vertebra, for measuring aol, by tracing the outline of muscle on plastic sheet of transparency and appropriate pen. we performed a quantitative analysis of the model accuracy using mean absolute percentage error, to measure the deviations. the lesser deviation was observed for grade-unesp, followed by the grade and geometric. grade-unesp method proved to be the more accurate compared to autocad, economically viable and applicable in the slaughter program, it was the most recommended for lamb carcass.