Patients with cancer are at increased risk of severe infections. From a cohort including 3060 patients with confirmed COVID-19, 109 (3.4%) cancer patients were included in this study. Among them, 23 (21.1%) patients died in the hospital. Cancer patients, especially those with hematological malignancies (41.6%), urinary carcinoma (35.7%), malignancies of the digestive system (33.3%), gynecological malignancies (20%), and lung cancer (14.3%), had a much higher mortality than patients without cancer. A total of 19 (17.4%) cancer patients were infected in the hospital. The clinical characteristics of deceased cancer patients were compared with those of recovered cancer patients. Multivariate Cox regression analysis indicated that a Nutritional Risk Screening (NRS2002) score≥3 (adjusted hazard ratio (HR) 11.00; 95% confidence interval (CI) 4.60–26.32; <0.001), high-risk type (adjusted HR 18.81; 95% CI 4.21–83.93; <0.001), tumor stage IV (adjusted HR 4.26; 95% CI 2.34–7.75; <0.001), and recent adjuvant therapy (<1 month) (adjusted HR 3.16; 95% CI 1.75–5.70; <0.01) were independent risk factors for in-hospital death after adjusting for age, comorbidities, D-dimer, and lymphocyte count. In conclusion, cancer patients showed a higher risk of COVID-19 infection with a poorer prognosis than patients without cancer. Cancer patients with high-risk tumor, NRS2002 score≥3, advanced tumor stage, and recent adjuvant therapy (<1 month) may have high risk of mortality.