OBJECTIVES: To study the mortality of patients with COVID-19 in Sierra Leone, to explore the factors associated with mortality during the COVID-19 pandemic and to highlight the complexities of treating patients with a novel epidemic disease in a fragile health system. STUDY DESIGN: A prospective single-centre cohort study. Data were extracted from paper medical records and transferred onto an electronic database. Specific indicators were compared between survivors and non-survivors, using descriptive statistics in Stata V.17. STUDY SETTING: The infectious diseases unit (IDU) at Connaught Hospital in Freetown, Sierra Leone PARTICIPANTS: Participants were all patients admitted to the IDU between March and July 2020. AIMS OF STUDY: The primary outcome of the study was to examine the all-cause mortality of hospitalised patients with suspected COVID-19 in Sierra Leone and the secondary outcome measures were to examine factors associated with mortality in patients positive for COVID-19. RESULTS: 261 participants were included in the study. Overall, 41.3% of those admitted to the IDU died, compared with prepandemic in-hospital mortality of 23.8%. Factors contributing to the higher mortality were COVID-19 infection (aOR 5.61, 95% CI 1.19 to 26.30, p=0.02) and hypertension (aOR 9.30, 95% CI 1.18 to 73.27, p=0.03) CONCLUSIONS: This study explores the multiple factors underpinning a doubling in facility mortality rate during the COVID-19 pandemic in Sierra Leone . It provides an insight into the realities of providing front-line healthcare during a pandemic in a fragile health system.