BACKGROUND: There were conflicting data regarding the effects of neoadjuvant therapy (NT) on the short-term outcomes of critically ill cancer patients. The aim of this study was to investigate whether NT adversely affect the short-term outcomes of critically ill cancer patients who underwent surgery. METHODS: This was a retrospective study which enrolled all critically ill cancer patients who admitted to intensive care unit (ICU) of Cancer Hospital of Chinese Academy of Medical Sciences and Peking Union Medical College between September 2017 and September 2018. Patients were divided into two groups: NT group and no NT (nNT) group. The primary outcome was ICU mortality rate. Propensity score analysis and Logistic regression analysis were used to investigate risk factors of ICU death. RESULTS: Hundred and twenty-eight patients received NT and 737 patients did not. The ICU mortality was higher in NT group than that in nNT group (3.9% vs. 1.4%, P=0.041) before propensity score matching analysis. After matching, there were no significant difference in ICU mortality between NT group and nNT group. Univariable logistic analysis demonstrated that a history of coronary heart disease (P=0.008), NT (P=0.041), unplanned admission to ICU (P<0.001), simplified acute physiology score (SAPS) 3 on ICU admission (P<0.001), sequential organ failure assessment (SOFA) on ICU admission (P<0.001), acute kidney injury (P<0.001), and mechanical ventilation (P<0.001) were predictive of ICU death in all 865 patients. Multivariable logistic regression analysis demonstrated that history of coronary heart disease (P=0.010; OR =9.614; 95% CI, 1.731-53.405), SAPS 3 on ICU admission (P=0.026; OR =1.070; 95% CI, 1.008-1.135) and SOFA on ICU admission (P=0.031; OR =1.289; 95% CI, 1.024-1.622) were independent risk factors of ICU death, while NT was not predictive of ICU death (P=0.118). CONCLUSIONS: NT was not a risk factor for ICU death in critically ill cancer patients who underwent surgery.