INTRODUCTION: Hypertension is often undiagnosed, untreated, undertreated, and poorly controlled. Many patients use the emergency department as their primary source of health care, and the emergency department represents an opportunity to identify undiagnosed hypertension. We sought to (1) identify the prevalence of elevated blood pressures in low-acuity patients and (2) describe the existing practice of reassessment, treatment, and referral of abnormal vital signs in these patients. METHODS: We conducted a retrospective study of 88 ED patients at an academic medical center. All patients meeting Emergency Severity Index level 4 or 5 criteria (low acuity) were eligible. The following variables were recorded: triage level, medical history and medications, disposition, and all blood pressures. The investigators independently reviewed and reached consensus regarding the following outcome variables: the need for and actual treatment of elevated blood pressure, and the need for and referral for blood pressure recheck after discharge. RESULTS: Thirty-seven patients (45%) had hypertension by definition on arrival. Systolic hypertension was more common. Ten of the patients (27%) with elevated blood pressures had documented rechecks prior to discharge in the emergency department, and only one patient was referred for follow-up. Twenty-seven out of 37 low-acuity patients (73%) who presented with elevated blood pressures had no documentation of the blood pressure being rechecked and no documentation of the patient being referred. CONCLUSION: Our data suggest that important opportunities for education and follow-up of hypertension are being missed.