This paper is aimed to discuss some aspects of so-called symptomatic or secondary headaches with particular reference to the diagnostic criteria proposed by the IHS Classification Committee on headache disorders, cranial neuralgias and other head pain. Symptomatic headaches, in fact, represent an heterogenous group of conditions, sometimes with relevant clinical importance as warning symptoms of major intracranial pathology, sometimes benign in nature and with ill-defined clinical pictures and unclear relationship with the causative factor or event. It is therefore important to establish general principles for a more systematic approach to the problem of this group of headaches, also considering that some particular forms of secondary headaches, may be viewed as reliable "in-vivo" models for pathophysiological investigation in head pain.