Background Hospital emergency MESHD departments play a crucial role in the initial management of suspected COVID-19 infection MESHD. We aimed to characterise patients attending emergency MESHD departments with suspected COVID-19, including subgroups based on sex, ethnicity and COVID-19 test results. Methods We undertook a mixed prospective and retrospective observational cohort study in 70 emergency MESHD departments across the United Kingdom (UK). We collected presenting data from 22446 people attending with suspected COVID-19 between 26 March 2020 and 28 May 2020. Outcomes were admission to hospital, COVID-19 result, organ support (respiratory, cardiovascular or renal), and death MESHD, by record review at 30 days. Results Adults TRANS were acutely unwell (median NEWS2 score 4) and had high rates of admission (67.1%), COVID-19 positivity (31.2%), organ support (9.8%) and death MESHD (15.9%). Children TRANS had much lower rates of admission (27.4%), COVID-19 positivity (1.2%), organ support (1.4%) and death MESHD (0.3%). Adult TRANS men and women presented in similar numbers (10210 versus 10506), but men were more likely to be admitted (72.9% v 61.4%), require organ support (12.2% v 7.7%) and die (18.7% v 13.3%). Black or Asian adults TRANS tended to be younger than White adults TRANS (median age TRANS 54, 50 and 67 years), were less likely to be admitted (60.8%, 57.3%, 69.6%) or die (11.9%, 11.2%, 16.8%), but were more likely to require organ support (15.9%, 14.3%, 8.9%) or have a positive COVID-19 test (40.8%, 42.1%, 30.0%). Adults TRANS admitted with confirmed COVID-19 had similar age TRANS and comorbidities (except chronic lung disease HP lung disease MESHD) to those who did not have COVID-19 confirmed, but were much more likely to need organ support (22.2% v 8.9%) or die (32.7% v 15.9%). Conclusions Important differences exist between patient groups presenting to the emergency MESHD department with suspected COVID-19. People with confirmed COVID-19 have a poor prognosis, compared with similar emergency MESHD admissions without confirmed COVID-19.