Hypertensive urgency is characterized by an acute increase in blood pressure without acute target organ damage, which is considered to be managed with close outpatient follow-up. However, limited data are available on the prognosis of these cases in emergency departments. We investigated the characteristics and predictors of all-cause mortality in Korean emergency patients with hypertensive urgency. This cross-sectional study included patients aged ≥18 years who visited an emergency tertiary referral center between January 2016 and December 2019 for hypertensive urgency, which was defined as a systolic blood pressure of ≥180 mmHg and a diastolic blood pressure of ≥110 mmHg, or both, without acute target organ damage. The 1 and 3 year all-cause mortality rates were 6.8% and 12.1%, respectively. The incidence of emergency department revisits and readmission after 3 months and 1 year was significantly higher in non-survivors than in survivors. In a multivariate analysis, age ≥ 60 years (hazard ratio (HR), 16.66; 95% CI, 6.20–44.80; p < 0.001), male sex (HR, 1.54; 95% CI, 1.22–1.94; p < 0.001), history of chronic kidney disease (HR, 2.18; 95% CI, 1.53–3.09; p < 0.001), and proteinuria (HR, 1.94; 95% CI, 1.53–2.48; p < 0.001) were independent predictors of 3 year all-cause mortality. The all-cause mortality rate of hypertensive urgency remains high despite the increased utilization of antihypertensive medications. Old age, male sex, history of chronic kidney disease, and proteinuria were poor prognostic factors for all-cause mortality in patients with hypertensive urgency.