Background. As the coronavirus disease 2019 (COVID-19) outbreak accelerates worldwide, it is important to evaluate sex-specific clinical characteristics and outcomes, which may affect public health policies. Methods. Patients with COVID-19 admitted to Tongji Hospital between 18 January and 27 March 2020 were evaluated. Clinical features, laboratory data, complications, and outcomes were compared between females and males. Risk factors for mortality in the whole population, females, and males were determined respectively. Results. There were 1667 (50.38%) females among the 3309 patients. The mortality rate was 5.9% in females but 12.7% in males. Compared with males, more females had no initial symptoms (11.1% vs 8.3%, P=.008). Complications including acute respiratory distress syndrome, acute kidney injury, septic shock, cardiac injury, and coagulation disorder were less common in females; critical illness was also significantly less common in females (31.1% vs 39.4%, P<.0001). Significantly fewer females received antibiotic treatment (P=.001), antiviral therapy (P=.025), glucocorticoids treatment (P<.0001), mechanical ventilation (P<.0001), and had intensive care unit admission (P<.0001). A lower risk of death was found in females (OR, .44; 95% CI, .34-.58) after adjusting for age and coexisting diseases. Among females, age, malignancy, chronic kidney disease, and days from onset to admission were significantly associated with mortality, while chronic kidney disease was not a risk factor in males. Conclusions. Significantly milder illness and fewer deaths were found in female COVID-19 inpatients and risk factors associated with mortality varied among males and females.