Purpose Oral corticosteroids (OCS) are commonly used in patients with severe asthma, but they are associated with several adverse events. We estimated the prevalence of patients with OCS-dependent asthma in a large nationwide registry for severe asthma and delineated their clinical characteristics. Methods This cross-sectional study analyzed enrollment data of the patients recruited in the Korean Severe Asthma Registry (KoSAR) from 2010 to 2019. The clinical characteristics of patients were compared according to OCS dependency, which was defined as maintenance OCS treatment lasting at least 6 months during the 12 months prior to enrollment. Results Among the 562 patients with severe asthma, 121 (21.5%) patients were defined as having OCS-dependent asthma. Compared with the OCS-independent group, the OCS-dependent group was older at symptom onset and had a higher prevalence of anxiety, worse lung function, and used more medication than the control group. Despite the higher doses of daily ICS and 6-month cumulative OCS, the OCS-dependent group reported greater consumption of relievers and a higher prevalence of unscheduled emergency room visits and repeated OCS bursts. Although anti-interleukin-5 was more commonly prescribed for patients with OCS-dependent asthma, only a limited proportion of patients with severe asthma received biologics. Conclusions One-fifth of patients with severe asthma had OCS-dependency, which was associated with a greater disease burden compared to those with OCS-independent asthma. Active intervention including initiation of biologics and regular assessment of OCS-induced morbidities is warranted to reduce the use of OCS and its potential adverse effects.