Objective: To compare the sex differences in the clinical findings among patients with severe coronavirus disease 2019 (COVID-19). Methods: We retrospectively collected data of 47 patients diagnosed as severe type of COVID-19 from February 8 to 22, 2020, including demographics, illness history, physical examination, laboratory test, management, and compared differences between men and women. Results: Of the 47 patients, 28 (59.6%) were men. The median age was 62 years, and 30 (63.8%) had comorbidities. The initial symptoms were mainly fever (34 [72.3%]), cough (36 [76.6%]), myalgia (5 [10.6%]) and fatigue (7 [14.9%]). Procalcitonin level was higher in men than in women (0.08 vs. 0.04ng/ml, p=0.002). N-terminal-pro brain natriuretic peptide increased in 16 (57.1%) men and 5 (26.3%) women (p=0.037). Five men (17.9%) had detected positive influenza A antibody, but no women. During 2-week admission, 5 (17.9%) men and 1 (5.3%) woman were reclassified into the critical type due to deterioration. Mortality was 3.6% in men and 0 in women respectively. Four (21.1%) women and one man (3.6%) recovered and discharged from hospital. Conclusion: Sex differences may exist in COVID-19 patients of severe type. Men are likely to have more complicated clinical condition and worse in-hospital outcomes as compared to women.