The main aim of this study is to look for early clinical markers of cerebral venous thrombosis (CVT). As headache represents the major clinical manifestation at presentation we focused our attention on this symptom. We present the preliminary results of a prospective multicentric study that includes cases diagnosed as CVT in the participating centres. We have so far studied 35 patients (5 males and 30 females) from the ages of 18 to 78. The most frequent manifestation was headache (77.1%). It was more frequently localised (66.7%) and continuous (77.8%). The onset of pain was mostly acute-subacute (38.5%-50.0%) and the intensity moderate-severe (37.0%-51.9%). On univariate analysis, we found a positive correlation between CVT, acute headache onset (p=0.001) and severe headache (p=0.004). These preliminary results seem in accordance with our previous findings in the retrospective study, suggesting that CVT is more often associated with acute-onset headache of severe intensity.