Simple SummaryCancer patients appear to be more vulnerable to COVID-19. This vulnerability can be explained by an immune-compromised status inherent to oncological disease and antitumoral treatments. Additionally, nosocomial exposure associated with regular medical visits and oncological treatments in the hospital context also contribute to the frailty of this group. Previously published studies have reported a superior mortality in COVID-19 oncological patients as well as more severe clinical evolution, with higher rates of admission to the intensive care unit (ICU) and intubation. However, there are few studies only involving cancer patients with COVID-19 admitted to the ICU. Therefore, this analysis is important from an epidemiological and clinical point of view. Furthermore, the comparison of COVID-19 cancer patients admitted to the ICU with a control group (non-cancer patients) limits the confounding factors and helps to determine whether cancer is a risk factor for adverse outcomes in the intensive care setting.AbstractCancer patients appear to be a vulnerable group in the COVID-19 pandemic. This study aims to compare clinical characteristics and outcomes of cancer and non-cancer patients with COVID-19 admitted to the ICU. All COVID-19 cancer patients (cases) admitted to a Portuguese ICU between March 2020 and January 2021 were included and matched on age, sex and comorbidities with COVID-19 non-cancer patients (controls); 29 cases and 29 controls were enrolled. Initial symptoms were similar between the two groups. Anemia was significantly superior among cases (76% vs. 45%;p= 0.031). Invasive mechanical ventilation (IMV) need at ICU admission was significantly higher among cases (48% vs. 7%; odds ratio (OR) = 12.600, 95% CI: 2.517–63.063,p= 0.002), but there were no differences for global need for IMV during all-length of ICU stay and mortality rates. In a multivariate model of logistic regression, the risk of IMV need at ICU admission among cases remained statistically significant (adjusted OR = 14.036, 95% CI: 1.337–153.111,p= 0.028). Therefore, compared to critical non-cancer patients, critical cancer patients with COVID-19 had an increased risk for IMV need at the moment of ICU admission, however, not for IMV need during all-length of ICU stay or death.