INTRODUCTION: To determine the prevalence of hunger and food insecurity among patients presenting to the emergency department (ED) over 3 consecutive years. METHODS: This was a cross-sectional study of patients presenting to the ED at Hennepin County Medical Center, and urban, Level I trauma center. We prospectively screened adult (age >18) patients presenting to the ED during randomized daily 8-hour periods between June 1 and August 31, 2007 and 2008, and randomized every-other-day periods between June 1 and August 31, 2009. We excluded patients with high acuity complaints, altered mental status, prisoners, those who did not speak Spanish or English, or those considered to be vulnerable. Consenting participants completed a brief demographic survey. The main outcome measures included age, gender, ethnicity, employment, housing status, insurance, access to food, and having to make choices between buying food and buying medicine. All responses were self reported. RESULTS: 26,211 patients presented during the study; 15,732 (60%) were eligible, 8,044 (51%) were enrolled, and 7,852 (98%) were included in the analysis. The rate of patients reporting hunger significantly increased over the 3-year period [20.3% in 2007, 27.8% in 2008, and 38.3% in 2009 (p<0.001)]. The rate of patients reporting ever having to choose between food and medicine also increased [20.0% in 2007, 18.5% in 2008, and 22.6% in 2009 (p=0.006)]. CONCLUSION: A significant proportion of our ED patients experience food insecurity and hunger. Hunger and food insecurity have become more prevalent among patients seen in this urban county ED over the past 3 years. Emergency physicians should be aware of the increasing number of patients who must choose between obtaining food and their prescribed medications, and should consider the contribution of hunger and food insecurity to the development of health conditions for which ED treatment is sought.