Transverse sinus stenosis is a common brain MRI finding in chronic migraine (CM) and chronic tension-type headache (CTTH) patients in clinical practice; however, its clinical and diagnostic role is unclear. The aim of the study is to determine the frequency of transverse sinus stenosis in these headache patients resistant to preventive treatments and to verify whether this is a useful finding for identifying patients with intracranial hypertension. This is an observational study. Patients with refractory CM and CTTH underwent a 3T-magnetic resonance venography (MRV) before cerebrospinal fluid (CSF) opening pressure measurement. Transverse sinus stenosis was determined using the combined conduit score. Patients with opening pressure >200 repeated MRV study 1 month after CSF withdrawal to evaluate changes in neuroimaging findings. We analyzed MRV studies of 40 patients (32 F, 8 M; mean age, 49.4 ± 10.8; mean body mass index, 26.7 ± 6.4; 39 CM and 1 CTTH with concomitant episodic migraine). Nineteen cases (47.5%) had evidence of transverse sinus stenosis: bilateral in seven patients (17.5%) and unilateral in 12 cases (30%). No statistically significant differences in transverse sinus stenosis distribution were found between patients with opening pressure <200 mmHO and those with opening pressure >200 mmHO. On Spearman bivariate test, there was no correlation between opening pressure and combined conduit score. No changes in neuroimaging findings were found 1 month after CSF withdrawal. Transverse sinus stenosis is a frequent radiological finding (47.5%) in CM and CTTH patients refractory to preventive treatments. However, this finding is not suggestive of intracranial hypertension. Whether transverse sinus stenosis may be a possible risk factor for chronic headache or a comorbidity needs to be evaluated in larger epidemiological studies.