Background: Hospitalized cancer patients (pts) with COVID-19 have a severe disease course and high mortality. Pts with lung cancer, hematologic malignancies and metastatic disease may be at higher risk. Detailed prospective inpatient data may help to identify those at greatest risk for poor outcomes. Methods: NCCAPS is a longitudinal study aiming to accrue 2,000 cancer pts undergoing treatment for hematologic malignancy or solid tumor with COVID-19. For pts’ first COVID-19 hospitalization, clinical data, research blood specimens and imaging are collected, and additional clinical data are collected during subsequent hospitalizations. Results: As of Jan. 22, 2021, among 757 enrolled adult patients from 204 sites, 124 (16.3%) reported at least one hospitalization for COVID-19, and discharge data was available for 98 hospitalizations in 88 patients. The median age was 67 (range 21-93, 1Q:56, 3Q:72), 35/88 (40%) were female. The most common malignancies in hospitalized adult pts were lymphoma (18.2%), lung cancer (15.9%) and multiple myeloma (10.2%). The most common presenting symptoms were shortness of breath (65%), fatigue/malaise (64%), and fever (49%). 8/88 (9%) pts were neutropenic (ANC < 1000) at presentation; 17/88 (19%) were thrombocytopenic. Median length of stay was 6.5 days (range 1-41, 1Q:4, 3Q:12). Among those hospitalized, 20/88 (22.7%) received care in the ICU or high dependency unit, with a median ICU stay of 7 days (range 1-22, 1Q:2.5, 3Q:9.5); of those admitted to the ICU, 25% (5/20) received invasive mechanical ventilation. Of those in whom inpatient medications were recorded (n = 63), 63% received corticosteroids, 46% received remdesivir, and 14% received convalescent plasma. One pt received bamlanivimab and 2 patients received tocilizumab. Most (46/63; 73%) received anticoagulation, primarily prophylactic low molecular weight heparin; 11/63 (17%) received therapeutic dose anticoagulation. Inpatient D-dimer values were recorded in 43 inpatients, 26 of whom had multiple measurements. 16/98 hospitalizations ended with death (16%). Conclusions: Preliminary analysis of NCCAPS data reveals that inpatient hospital admission is common among oncology patients with COVID-19 and mortality rates appear high within this cohort. Hematologic malignancies and lung cancer are the most common underlying diagnoses in patients requiring hospitalization. Corticosteroids and anti-coagulation were the most commonly used therapies. Despite high rates of ICU admission, invasive mechanical ventilation may be instituted less often in an oncology cohort. These observations may inform decisions about vaccine policy and decisions to limit life sustaining treatment. Clinical trial information: NCT04387656