T he reported prevalence of gastrointestinal (GI) symptoms, including anorexia, diarrhea, nausea, vomiting, and abdominal pain, in severe acute respiratory syndrome coronavirus 2 infection has been highly variable, ranging from 5% to 61%. 1-7 Although the Centers for Disease Control and Prevention guidelines for testing for coronavirus disease 2019 (COVID-19) include vomiting and diarrhea, to our knowledge, all studies to date have been retrospective, and none have evaluated the prevalence of GI symptoms among patients who tested negative for COVID-19. In this prospective case-control study, we compared the prevalence of GI symptoms between those who tested positive and negative for COVID-19 and determined the association between GI symptoms and COVID-19 diagnosis or outcomes. Methods This was a prospective case-control study performed at a single tertiary care hospital in Baltimore, Maryland, after institutional review board approval. The study population included all adult patients who tested positive (case patients) or negative (control individuals) for COVID-19 by nasopharyngeal swab between March 9, 2020, and April 15, 2020. A telephone survey was conducted to obtain information including demographics, comorbid conditions, GI symptoms, respiratory symptoms, fever, gustatory symptoms, olfactory symptoms, and need for hospitalization by using a predesigned questionnaire. The primary outcome was the prevalence of GI symptoms in COVID-19-positive and-negative patients, and the secondary outcomes were to determine the utility of GI symptoms for COVID-19 screening and the association of GI symptoms with need for hospitalization. Logistic regression and univariate followed by multivariable analysis using a backward model selection approach were conducted to evaluate risk factors of COVID-19, and the area under the receiver operating characteristic (AUROC) for COVID-19 using a combination of different symptoms was determined.