Background <p>Sigmoid sinus dehiscence has lately been identified as one of the major important causes of venous pulsatile tinnitus. Dehiscence in the sigmoid plates develops as a result of sustained, intense blood flow pressure that increases with age. Some studies outlined the connection between vitamin D insufficiency and tinnitus. To the best of our knowledge, no prior research has explored the link between vitamin D deficiency and its potential role as an underlying cause of sigmoid sinus dehiscence, due to weak cortical bones and osteoporosis, and pulsatile tinnitus triggered by this dehiscence.</p> Aim of the work <p>The work seeks to evaluate the prevalence of vitamin D insufficiency in patients with pulsatile tinnitus because of a dehiscent sigmoid sinus.</p> Patients and methods <p>A cross-sectional study was carried out on 36 patients with dehiscent sigmoid sinuses and, hence, pulsatile tinnitus who presented to Ain Shams University Hospitals from December 2023 to December 2024.</p> Results <p>A direct significant relation was found between sigmoid sinus dehiscence and tinnitus as the more increase in severity in the degree of dehiscence, the more increase in the degree of tinnitus. The correlation between sigmoid sinus dehiscence and vitamin D levels showed a negative significant relation: the more reduced vitamin D levels, the more dehiscence. Correlation between the degree of tinnitus and vitamin D levels showed a negative significant relation: the more reduction in vitamin D levels, the more tinnitus.</p> Conclusion <p>Vitamin D deficiency may be an important factor in pulsatile tinnitus caused by dehiscent sigmoid plates. Further studies are needed to evaluate the effectiveness of the supplementation of vitamin D in controlling symptoms of pulsatile tinnitus in those cases.</p>