To investigate the association of blood pressure and end-organ damage in patients with severe hypertension in a case-controlled manner, 26 patients with syndromes of acute end-organ damage and severe hypertension were compared with 25 patients with severe but asymptomatic hypertension for a variety of demographic, clinical, and basic laboratory values. Differences were assessed with the Chi-square test and multiple logistic regression analysis. End-organ damage was significantly associated with a degree of systolic and diastolic blood pressure elevation, a history of hypertensive crisis, serum creatinine, and a history of alcohol use, in multivariate analysis. The relationship to creatinine and a history of hypertensive crisis were not present in univariate analysis. The possible relationships of these factors to the pathophysiology of hypertensive crisis are discussed.