The Vienna classification of Crohn’s disease provides defined criteria for a phenotypic classification of the disease, considering that phenotypic parameters reflect the contribution of both genetic and environmental factors to the expression of disease. The classification includes mainly three criteria as part of the natural course of disease: age at the diagnosis, location and behaviour and it provides distinct definitions to categorize Crohn’ patients into 24 subgroups. In this study we attempt to define the clinical importance of the Vienna classification and the possibility to optimize medical care of Crohn’s disease according to patient subgroups. Early age at the diagnosis is associated with a greater prevalence of a family history, greater small bowel involvement, more complicated stricturing disease and a higher frequency of surgery. Surgery is based on exact knowledge of location: L1 patients might profit the most from resective surgery, L4 patients from strictureplasty. Stricturing behaviour (B2) might be the most appropriate subgroup for surgical treatment. Penetrating behaviour (B3) is confirmed as an important risk for early postoperative recurrence; patients in the penetrating behaviour group (i.e. fistulas) have a specific indication for immunosuppressive or anti-tumour necrosis factor-α therapy.