Patients with celiac disease have varying degrees of damage to the small intestinal mucosa, ranging from lymphocytic duodenosis with normal villous structure to severe villous atrophy. We assessed whether the severity of mucosal lesions was associated with clinical and laboratory features of celiac disease.We compared demographic, clinical, and laboratory characteristics among patients with celiac disease who were classified based on the severity of duodenal lesions. We analyzed data from 1408 adult patients seen consecutively at a tertiary referral center since 1990. Patients were classified as having villous atrophy (n = 1249) or as having mild enteropathy (n = 159) in the presence or absence of villous atrophy.Similar percentages of patients with villous atrophy, vs mild enteropathy, experienced weight loss (17% vs 17%), gastrointestinal manifestations (70% vs 70%), extraintestinal manifestations (66% vs 57%), and other associated conditions (19% vs 23%). More patients with villous atrophy than patients with mild enteropathy developed osteopenia or osteoporosis (22% vs 5%; P = .0005). Greater percentages of patients with villous atrophy than those with mild enteropathy also had anemia (42% vs 29%; P = .002), folate deficiency (75% vs 64%; P = .02), hypocholesterolemia (7% vs 2%; P = .02), hypocalcemia (26% vs 13%; P = .004), or hyperparathyroidism (45% vs 29%; P = .004).Although osteopenia, osteoporosis, and alterations in laboratory parameters are prevalent among patients with celiac disease with mild enteropathy, they are more prevalent and severe in those with villous atrophy. The prevalence of associated conditions is similar between these groups. These results indicate that celiac disease with mild enteropathy is not mild disease, but requires treatment with a gluten-free diet.