Background: COVID-19 infections have been known to cause worse outcomes in patients with underlying co-morbid conditions. Currently, there is limited data regarding re-admissions in such patients after COVID-19 infection. So, we pursued to assess the rates, predictors, and causes of re-admission after COVID-19 infection in patients who had underlying gastrointestinal malignancy. Methods: The National Readmission Database for 2020 was analyzed to identify patients with COVID-19 hospitalizations who also had a co-diagnosis of GI malignancy. Data for re-admission was gathered, at 30 and 90 days after initial hospitalization. Multivariate logistic and linear regression analysis was used accordingly to adjust for possible confounders. Results: For 30 days: A total of 2,726 COVID-19 hospitalizations had a co-diagnosis of GI malignancy. The mean LOS (length of stay) for index admission was 8.7 days. The mean TOTCHG (total hospital charge) for index admission was $85,747. Within 30 days from discharge, 462 (21%) were re-admitted. The in-hospital mortality in re-admissions (18.4%) was quite similar to that for index hospitalization (18.5%). Positive predictors of re-admission include shorter length of stay during initial hospitalization (<3 days), anemia, renal insufficiency/chronic kidney disease, and atherosclerosis of the aorta. Females had a lower chance of re-admission compared to males. Among the top causes of re-admission were ongoing COVID-19 infection (27%), sepsis (16.3%), acute kidney injury (2.4%), and metabolic encephalopathy (1.2%). For 90 days: A total of 1,782 COVID-19 hospitalizations had a co-diagnosis of GI malignancy. The mean LOS (length of stay) for index admission was 9.2 days. The mean TOTCHG (total hospital charge) for index admission was $90,908. Within 90 days from discharge, 411 (29%) were re-admitted. The in-hospital mortality in readmissions (14%) was lower than that for index hospitalization (20.3%). Predictors of re-admissions include secured insurance, anemia, renal insufficiency/chronic kidney disease, and cerebrovascular accidents. Top causes of re-admission were ongoing COVID-19 infection (18.5%), aspiration pneumonitis (2.9%), pneumonia (2.3%), and acute kidney injury (1.4%). Conclusions: Infections were the leading cause of re-admission, which is an important factor to consider when managing patients with GI malignancies due to sub-optimal immunity. Among these patients, those with concomitant anemia and chronic kidney disease were more prone to being re-admitted. Patients with GI malignancies also tended to have a higher length of stay, leading to higher charges, more exposure to nosocomial infections, and delays in cancer treatment leading to worse cancer outcomes. Pre-mature discharges, without medical optimization, can also potentially predispose to higher rates of re-admissions.