BACKGROUND & AIMS: Celiac disease is a common disorder with a worldwide distribution, although the prevalence among different ethnicities varies. We aimed to measure the prevalence of duodenal villous atrophy among patients of different ethnicities throughout the United States. METHODS: We performed a cross-sectional study of all patients who had duodenal biopsies submitted to a national pathology laboratory between January 2, 2008 and April 30, 2015. The prevalence of villous atrophy was calculated for the following ethnicities by using a previously published algorithm based on patient names: North Indian, South Indian, East Asian, Hispanic, Middle Eastern, Jewish, and other Americans. RESULTS: Among all patients (n = 454,885), the median age was 53 years, and 66% were female. The overall prevalence of celiac disease was 1.74%. Compared with other Americans (n = 380,163; celiac disease prevalence, 1.83%), celiac disease prevalence was lower in patients of South Indian (n = 177, 0%; P = .08), East Asian (n = 4700, 0.15%; P <= .0001), and Hispanic (n = 31,491, 1.06%; P <= .0001) ethnicities. Celiac disease was more common in patients from the Punjab region (n = 617, 3.08%) than in patients from North India (n = 1195, 1.51%; P =.02). The prevalence of celiac disease among patients of Jewish (n = 17,806, 1.80%; P = .78) and Middle Eastern (n = 1903, 1.52%; P = .33) ethnicities was similar to that of other Americans. Among Jewish individuals (n = 17,806), the prevalence of celiac disease was 1.83% in Ashkenazi persons (n = 16,440) and 1.39% in Sephardic persons (n = 1366; P = .24). CONCLUSIONS: Among patients undergoing duodenal biopsy, individuals from the Punjab region of India constitute the ethnic group in the United States with the highest prevalence of villous atrophy consistent with celiac disease. Compared with other Americans, villous atrophy prevalence on duodenal biopsy is significantly lower among U.S. residents of South Indian, East Asian, and Hispanic ancestry.