OBJECTIVE: The aim of our study was to establish whether or not tinnitus patients have higher platelet activity, as measured by plasma 11-dehydro-thromboxane B2 levels, compared with individuals without tinnitus. METHODS: The study group included patients without documented organic causes of tinnitus or a cause of non-vascular hearing impairment. Laboratory tests included complete blood count, biochemistry, coagulation activity, and thromboxane levels. To exclude a pathology in the cerebellopontine angle, CT and MRI were performed together with an X-ray scan of cervical vertebrae. For the purpose of this study, blood samples were screened for 11-dehydro-thromboxane B2 levels using commercial kits. RESULTS: A comparison of the main marker of increased platelet activity i.e., thromboxane levels of tinnitus patients with those of a control group, showed increased thromboxane levels in the former. The average plasma concentrations of 11-dehydro-thromboxane B2 were 2.0234±1.80 ng/ml in the group of tinnitus patients and 1.3247±1.33 ng/ml in the control group. Our results showed that patients with tinnitus have significantly higher values of 11-dehydro-thromboxane B2. CONCLUSION: Tinnitus patients showed higher levels of increased platelet activity, a marker that may play an important role in the pathogenesis of tinnitus.