Objective: The objectives of this study were to clarify whether prevertebral soft tissue (PVST) thickening increases the risk of dysphagia, to identify at which vertebral level determining PVST thickness is useful, and to determine cutoff values. Methods: A total of 80 patients with traumatic cervical spinal cord injury (TCSCI) treated over a 43-month period at a single regional institution specializing in cervical spinal cord injuries participated in the study. The exclusion criteria were having undergone anterior cervical spine surgery; a history of complicated traumatic brain injury, complicated vertebral artery injury, or brain injury; endotracheal intubation at day 30 after onset; the disappearance of neurological symptoms within 24 hours after onset; and the use of a halo vest. The associations between PVST thicknesses at C1, C2, C3, C6, and C7 measured by CT on the day of onset and the presence of dysphagia (Food Intake LEVEL Scale score <8) at 30 and 60 days after onset of TCSCI were analyzed using ROC curves to calculate the maximum area under the curve and the PVST cutoff values for these vertebrae. Associations between various risk factors, including PVST thickness, and dysphagia at days 30 and 60 after onset were examined using univariate and multivariate analyses. Results: Independent associations with dysphagia were found with the C3 PVST thickness (day 30: ≥8.3 mm, day 60: ≥9.4 mm) and tracheostomy. Conclusion: PVST thickness or injury seems to be an independent risk factor for dysphagia. By measuring PVST, it is possible to estimate the severity of dysphagia even in acute conditions.