Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a rare, severe mucocutaneous reaction with few large cohorts reported. This multicenter retrospective study included patients with SJS/TEN seen by inpatient consultative dermatologists at 18 academic medical centers in the United States. A total of 377 adult patients with SJS/TEN between January 1, 2000 and June 1, 2015 were entered, including 260 of 377 (69%) from 2010 onward. The most frequent cause of SJS/TEN was medication reaction in 338 of 377 (89.7%), most often to trimethoprim/sulfamethoxazole (89/338; 26.3%). Most patients were managed in an intensive care (100/368; 27.2%) or burn unit (151/368; 41.0%). Most received pharmacologic therapy (266/376; 70.7%) versus supportive care alone (110/376; 29.3%)—typically corticosteroids (113/266; 42.5%), intravenous immunoglobulin (94/266; 35.3%), or both therapies (54/266; 20.3%). Based on day 1 SCORTEN predicted mortality, approximately 78 in-hospital deaths were expected (77.7/368; 21%), but the observed mortality of 54 patients (54/368; 14.7%) was significantly lower (standardized mortality ratio = 0.70; 95% confidence interval = 0.58–0.79). Stratified by therapy received, the standardized mortality ratio was lowest among those receiving both steroids and intravenous immunoglobulin (standardized mortality ratio = 0.52; 95% confidence interval 0.21–0.79). This large cohort provides contemporary information regarding US patients with SJS/TEN. Mortality, although substantial, was significantly lower than predicted. Although the precise role of pharmacotherapy remains unclear, co-administration of corticosteroids and intravenous immunoglobulin, among other therapies, may warrant further study.