The "ad hoc" Study Group of the Federation of Italian Anticoagulation Clinics has proposed a series of guidelines for oral anticoagulant therapy in different pathological states for which this treatment is indicated. These indications are based on the scientific literature available through March 1996. While there is wide consensus for some indications, opinions diverge regarding others. Finally, there are a number of indications which are potentially useful but are not supported by adequate studies. For the applications of guidelines in individual cases, however, careful clinical evaluation is necessary.