Purpose <p>Plentiful evidence points to a significant correlation between paravertebral muscles and spinal diseases. Yet, no reports are available detailing the association between paravertebral muscle status and diffuse idiopathic skeletal hyperostosis (DISH). The purpose of this retrospective study was to assess the link between paravertebral muscle area as well as fat infiltration and DISH based on computer tomography.</p> Methods <p>Data were obtained from patients with acute vertebral fractures who presented to a single spine center. All participants had whole spine lateral x-ray radiography for DISH diagnosis. Those with a history of spinal disease, fusion surgery, or tumors were excluded. Patients with or without DISH were propensity-matched by age, sex, and body mass index (BMI). Appropriate Mann-Whitney U-tests or independent t-tests were performed to evaluate the correlation between muscle area or fat infiltration of the L3 level paravertebral muscles and DISH.</p> Results <p>A total of 114 DISH and 114 non-DISH patients were assessed. The fat infiltration in the paravertebral muscles was remarkably higher in the DISH group than in the non-DISH (<i>p</i> &lt; 0.05), whereas there was no statistical difference in the muscle area of the two (<i>p</i> &gt; 0.05).</p> Conclusion <p>In conclusion, the fat infiltration of the paravertebral muscles was significantly associated with DISH.</p>