Nielsen MG, et al. – Purpose of this investigation was to validate the web–based version of the Major Depression Inventory (MDI) against a fully structured telephone interview in a population selected on clinical suspicion of depression in general practice. Findings revealed that the MDI is a conservative instrument for diagnosing International Classification of Diseases, Tenth Revision (ICD-10) depression in a clinical setting compared to the Munich–Composite International Diagnostic Interview (M–CIDI) interview. However, only a few false–positive diagnoses were detected when the MDI was used on clinical suspicion of depression.