ABSTRACT: Study Design. A prevalence and reliability study of Modic changes in the cervical spine.Objective. To assess the prevalence and reliability of diagnosing and classifying Modic changes and their relationship to disc herniations in the cervical spine.Summary of Background Data. Degenerative marrow (Modic) changes in the spine can be seen on MRI with some evidence linking them to pain. Many studies have been published on Modic changes in the lumbar spine, but only 1 small prevalence study focusing on Modic changes in the cervical spine has been reported.Methods. The cervical MRI scans of 500 patients over the age of 50 were retrospectively evaluated for the prevalence, type and location of Modic changes and disc herniations. 200 of these same scans were independently analyzed by a second observer to evaluate interobserver reliability of diagnosis with 100 re-evaluated by the same observer 1 month later to assess intraobserver reliability. The SPSS program and Kappa statistics were used to assess prevalence and reliability. The risk ratio comparison of DH and MC was calculated.Results. 426 patients (85.2 %) met the inclusion criteria. Modic changes were observed in 40.4% of patients (14.4% of all motion segments). 4.3% were type 1 and 10.1% were type 2. Disc herniations were seen in 78.2% of patients (13.3% of motion segments). Both MC and DH were most frequently observed at C5/6 and C6/7. Disc extrusions were positively associated with MC (RR = 2.4). The reliability demonstrated an upper moderate interobserver (k = 0.54) and an almost perfect intraobserver agreement (k = 0.82).Conclusions. A high prevalence of Modic changes was observed with type 2 predominating. The C5/6 and C6/7 levels are most effected. Patients with MC are more likely to have a disc herniation at the same level. MC type 2 predominates. The classification is reliable.