Blacks/African Americans are overrepresented in the number of hospitalizations and deaths from COVID-19 in the United States, which could be explained through differences in the prevalence of existing comorbidities. We performed a disease-disease phenome-wide association study (PheWAS) using data representing 5,698 COVID-19 patients from a large academic medical center, stratified by race. We explore the association of 1,043 pre-occurring conditions with several COVID-19 outcomes: testing positive, hospitalization, ICU admission, and mortality. Obesity, iron deficiency anemia and type II diabetes were associated with susceptibility in the full cohort, while ill-defined descriptions/complications of heart disease and stage III chronic kidney disease were associated among non-Hispanic White (NHW) and non-Hispanic Black/African American (NHAA) patients, respectively. The top phenotype hits in the full, NHW, and NHAA cohorts for hospitalization were acute renal failure, hypertension, and insufficiency/arrest respiratory failure, respectively. Suggestive relationships between respiratory issues and COVID-19-related ICU admission and mortality were observed, while circulatory system diseases showed stronger association in NHAA patients. We were able to replicate some known comorbidities related to COVID-19 outcomes while discovering potentially unknown associations, such as endocrine/metabolic conditions related to hospitalization and mental disorders related to mortality, for future validation. We provide interactive PheWAS visualization for broader exploration.