Introduction In a consensus statement, the Academy of Nutrition and Dietetics (AND) and the American Society for Parenteral and Enteral Nutrition (ASPEN) introduced the malnutrition clinical characteristics (MCC). The MCC encompasses a standardized set of characteristics that clinicians can assess to support a diagnosis of malnutrition. Studies utilizing this tool in patients undergoing orthotopic heart transplant (OHT) or placement of a left ventricular assist device (LVAD) are limited. Hypothesis Malnutrition as identified using a modified MCC is associated with greater lengths of stay and rates of readmission following OHT or LVAD placement. Methods A single-center retrospective review of 240 completed nutrition assessments using a modified MCC in patients who underwent OHT (n= 70) or LVAD placement (n=170) between January 2016 and February 2020 was performed. Four MCC characteristics were assessed: weight loss, decreased energy intake, body fat depletion and muscle mass loss. A diagnosis of malnutrition was determined for patients who met two or more of the characteristics (MCC ≥ 2, n= 153). Patients who met less than two of the characteristics did not meet criteria for diagnosis of malnutrition (MCC < 2, n = 87). Comparisons were made between groups using Mann-Whitney U and Chi-Square tests where appropriate. All tests were two-tailed and a p-value of <0.05 was considered statistically significant. Primary outcome was hospital length of stay (LOS). Secondary outcomes included total ICU LOS, post-operative ICU LOS and 30-day readmission. Results No significant difference in age, gender, ethnicity or baseline comorbidities was observed between groups. BMI was significantly lower among patients with an MCC ≥ 2 (26.5, IQR 23.4-31.9) compared to MCC < 2 (29.9, IQR 26.5-34.0, p<0.01). Primary outcome of hospital LOS was significantly greater among patients with an MCC ≥ 2 (p<0.01, table 1). Secondary outcomes of total ICU LOS, post-operative ICU LOS and 30-day readmission were significantly greater among patients with an MCC ≥ 2 compared to MCC < 2 (p<0.01, table 1). Conclusion Malnutrition as identified using a modified MCC was associated with significantly greater hospital and ICU lengths of stay and rates of 30-day readmission following OHT or LVAD placement. In a consensus statement, the Academy of Nutrition and Dietetics (AND) and the American Society for Parenteral and Enteral Nutrition (ASPEN) introduced the malnutrition clinical characteristics (MCC). The MCC encompasses a standardized set of characteristics that clinicians can assess to support a diagnosis of malnutrition. Studies utilizing this tool in patients undergoing orthotopic heart transplant (OHT) or placement of a left ventricular assist device (LVAD) are limited. Malnutrition as identified using a modified MCC is associated with greater lengths of stay and rates of readmission following OHT or LVAD placement. A single-center retrospective review of 240 completed nutrition assessments using a modified MCC in patients who underwent OHT (n= 70) or LVAD placement (n=170) between January 2016 and February 2020 was performed. Four MCC characteristics were assessed: weight loss, decreased energy intake, body fat depletion and muscle mass loss. A diagnosis of malnutrition was determined for patients who met two or more of the characteristics (MCC ≥ 2, n= 153). Patients who met less than two of the characteristics did not meet criteria for diagnosis of malnutrition (MCC < 2, n = 87). Comparisons were made between groups using Mann-Whitney U and Chi-Square tests where appropriate. All tests were two-tailed and a p-value of <0.05 was considered statistically significant. Primary outcome was hospital length of stay (LOS). Secondary outcomes included total ICU LOS, post-operative ICU LOS and 30-day readmission. No significant difference in age, gender, ethnicity or baseline comorbidities was observed between groups. BMI was significantly lower among patients with an MCC ≥ 2 (26.5, IQR 23.4-31.9) compared to MCC < 2 (29.9, IQR 26.5-34.0, p<0.01). Primary outcome of hospital LOS was significantly greater among patients with an MCC ≥ 2 (p<0.01, table 1). Secondary outcomes of total ICU LOS, post-operative ICU LOS and 30-day readmission were significantly greater among patients with an MCC ≥ 2 compared to MCC < 2 (p<0.01, table 1). Malnutrition as identified using a modified MCC was associated with significantly greater hospital and ICU lengths of stay and rates of 30-day readmission following OHT or LVAD placement.