Since the pathogenesis of psoriasis vulgaris is now understood as a T cell mediated systemic auto-immune disease, the awareness for the potential systemic implications of the chronic active inflammation has grown. By evaluation of patient registries and study data, several complexes of comorbidities could be identified in recent years, albeit not all of them being clinically relevant. Comorbidity in this context will be defined as two or more diagnostically distinguished medical conditions existing simultaneously, but without a causal link. Nevertheless, there is some strong indication for pathogenetic link between some specified comorbidities and psoriasis at molecular and immunological level. The need for an interdisciplinary assessment of the potential interrelation is obvious. In order to detect the individual risk for comorbidities in patients with moderate to severe psoriasis and to recommend the course of action, a checklist has been developed at an interdisciplinary level that is reduced to the quintessential points for the use in daily practice.