Parenteral nutrition (PN) exacerbates hyperglycemia, which is associated with increased morbidity and mortality in various cancer populations. Using a retrospective design, we examined incident hyperglycemia in PN and non-PN recipients and the associations with clinical events and 5-year survival in a cohort treated for myeloma with melphalan and auto-SCT (n=112). Clinical comparisons were made at admission, and “before” and “after” initiating PN to discern differences and temporality. Actual infusion times were used for PN patients; timeframes based on mean PN infusion days were created for the non-PN recipients. Oral intake was lower “before” in PN vs. non-PN patients (p=<0.001); however, no differences in mucositis, emesis, infections or transfusions were detected “before.” Incident hyperglycemia (≥7.0 mmol/L) was significant “after” PN initiation, and PN recipients experienced delays in WBC (p<0.05) and platelet engraftment (p= 0.009) and required significantly greater RBC (p=0.0014) and platelet (p=0.001) support “after” than non-PN patients. Neutropenic fever and longer hospital stay were more frequent among PN vs. non-PN recipients (p<0.001). Differences in 5-year mortality were not apparent. Findings fail to support clinical benefits of PN administration during auto-SCT for myeloma. Further study is needed to discern if hyperglycemia or feeding per se was deleterious in this patient population.