Background: With movement towards value-based care, institutions seek ways to reduce costs by decreasing inpatient stays. A multidisciplinary approach to supportive care, especially when provided early, is one way to realize value-based care. We assess the impact of pre-admission versus post-admission involvement of an Integrated Supportive Care Model (ICSM) on inpatient length of stay (LOS) at a NCI-designated cancer center. Methods: Data was collected from 2014 to 2016 at City of Hope. The Integrated Supportive Care Model at City of Hope includes: palliative care, psychiatry, psychology, interventional pain, social work, child-life, distress screening, and couples program. “Pre-admission” was defined as seeing at least one service prior to hospital admission; “Post-admission” defined as seeing at least one service during admission. “Short LOS” for hematology patients was categorized as ≤ 14 days and for oncology patients as ≤ 3 days. Continuous LOS between patients receiving an ISCM intervention pre- and post-admission was compared using Kruskal-Wallis test. Univariate and multivariable logistic regression was done to examine association between involvement of ISCM pre- and post-admission and categorical LOS. P-values < 0.05 were considered statistically significant. Results: 1,627 (809 with hematologic malignancy, 818 with oncologic malignancy) patients with only one hospitalization during the study time were included. For hematology patients, involvement with the ISCM pre-admission was associated with shorter LOS ( ≤ 14 days) compared with involvement post-admission (29.3 vs 11.1%, multivariable OR = 4.08, P < 0.001). Median LOS for hematology patients who participated in the ISCM pre-admission was shorter than those who received ISCM services post-admission (21 vs. 22 days, p = 0.049). Similarly, for oncology patients, ISCM involvement pre-admission was associated with shorter LOS ( ≤ 3 days) compared to involvement post-admission (91.4% vs 8.6%, multivariable OR = 3.74, P < 0.001). Median LOS for oncology patients who received an ISCM intervention pre-admission was shorter than those who received an ISCM intervention post-admission (2 vs. 6 days, p < 0.001). Conclusions: In hematologic and oncologic malignancies, use of an ISCM prior to patient’s first hospitalization is associated with significantly shorter LOS compared with those who received ISCM services during the hospital stay. This suggests efforts should be made to include an ISCM early in the trajectory of illness, prior to first hospitalization.