Coeliac disease, a life-long gluten-sensitive disorder, characterized by malabsorption, villous atrophy and crypt hyperplasia, is well recognized. However, the disease is evidently underdiagnosed, and the classic forms constitute only the tip of the 'coeliac iceberg'. Patients with coeliac disease can have subtle symptoms, if any. Diagnostic difficulties may further emerge when minor mucosal changes are found. In coeliac screening and case-finding a novel test, the antitissue transglutaminase test, has proven promising with a sensitivity and specificity of over 95 %. Genetic and immunohistological research has taken a great leap forward. Coeliac disease is strongly associated with HLA-DQ2, coded by the DQA1*0501 and DQB1*02 alleles, or the DQ8 (DQA1*03, DQB1*0302 alleles). The disease is rare in patients who do not share these alleles, a circumstance which can be utilized in diagnostics. An increase in small bowel intraepithelial lymphocytes especially gammadelta+ T-cell receptor-bearing cells is typical, albeit not pathognomonic, for coeliac disease. Combining new symptoms, humoral immunity, genetics and immunohistological staining can today offer a greater diagnostic scope for coeliac disease, especially in cases where clinical presentation and small bowel biopsy findings remain doubtful.