Some patients with undiagnosed celiac disease have minor mucosal lesions that may not be apparent during routine histological analysis. Twenty-five such patients of our institution were discharged to their primary-care physicians despite having positive endomysial antibody serology. To re-evaluate diagnosis for these patients, immunohistological staining with antibodies to CD2, CD3, CD7, CD8, CD69, and Ki67 was conducted on original biopsies from twenty patients. Clinical, serological, and histological investigations were offered to all fourteen patients who attended for review. We observed a significantly greater (P < 0.0001) numbers of intraepithelial lymphocytes and Ki67-positive enterocytes in sections from these twenty patients than for normal controls. Of the fourteen patients who attended for further review, firm diagnosis of celiac disease was made for seven patients and diagnosis was likely for another two. Our study clearly revealed that over-reliance on standard histological findings results in failure to diagnose celiac disease.