Previous studies have suggested a more frequent and severe course of novel coronavirus SARS-CoV-2 infection in cancer patients undergoing active oncologic treatment. Our aim was to describe the characteristics of the disease in this population and to determine predictive factors for poor outcome in terms of severe respiratory distress (acute respiratory distress syndrome ARDS) or death. Patients consecutively admitted for SARS-CoV-2 infection were prospectively collected, and retrospective statistical analysis was performed. Univariate and multivariate analyses were performed to assess potential factors for poor outcomes defined as ARDS or death. Sixty-three patients were analysed, and 34 of them developed respiratory failure (70% as ARDS). Lymphocytes/mm3 (412 versus 686; p = 0.001), serum albumin (2.84 versus 3.1); lactate dehydrogenase (LDH) (670 versus 359; p < 0.001) and C-reactive protein (CRP) levels (25.8 versus 9.9; p < 0.001) discriminate those that developed respiratory failure. Mortality rate was 25%, significantly higher among ARDS, neutropenic patients (p = 0.01) and in those with bilateral infiltrates (44% versus 0%; p < 0.001). Multivariate logistic analyses model confirmed the predictive value of severe neutropenia (odds ratio OR 16.54; 95% confidence interval CI 1.43–190.9, p 0.025), bilateral infiltrates (OR 32.83, CI 95% 3.51–307, p 0.002) and tumour lung involvement (OR 4.34, CI 95% 1.2–14.95, p 0.02). Cancer patients under active treatment admitted for SARS-CoV-2 infection have worse outcomes in terms of mortality and respiratory failure rates compared with COVID-19 global population. Lymphopenia, LDH, CRP and albumin discriminate illness severity, whereas neutropenia, bilateral infiltrates and tumour pulmonary involvement are predictive of higher mortality. •Cancer patients are supposed to be especially vulnerable for SARS-CoV-2 infection.•Active cancer treatment could be deleterious in case of simultaneous SARS-CoV-2 infection.•Outcomes of patients under treatment and admitted for SARS-CoV-2 infection are described.•Hospitalised SARS-CoV-2 cancer patients show similar death rate to non-cancer patients.