Background: Skeletal Muscle Density (SMD) is the amount of fat infiltration in the muscle, Low SMD (myosteatosis), is associated with chemotherapy toxicity in women with breast cancer (BC); however, cut points are not consistent across studies. We investigated the association of alternative cut-points for low SMD at BC diagnosis and adverse outcomes during chemotherapy in women with early BC. Methods: This is a retrospective chart review. Axial CT images were evaluated at the L3 level to calculate average SMD in Hounsfield Units (HU). Three cut points (Table) classified patients as low versus normal SMD. T-test was used to calculate the relative risk (RR) for adverse events. Results: In 340 patients, the mean age was 51. Table shows RR for three adverse events (dose reduction, early treatment discontinuation, hospitalization) for each of the three cut points. Conclusions: All three cut-points described in the literature are reliable for stratification of patients with EBC for myosteatosis and associated chemotherapy-related adverse events.