OBJECTIVE: To investigate preoperative factors affecting the presence of intramedullary increased signal intensity (ISI) on T2-weighted magnetic resonance imaging (MRI) in patients with cervical spondylotic myelopathy (CSM) and the impact of ISI on clinical manifestations. PATIENTS AND METHODS: Eighty-nine patients with CSM were retrospectively reviewed from January 2013 to December 2016 in our hospital. Based on the presence or absence of ISI on axial and sagittal T2-weighted MRI, patients were divided into ISI group (48 cases) and non-ISI group (41 cases). Factors such as age, sex, body mass index (BMI), duration of symptoms, clinical symptoms and signs, number and distribution of spinal cord compression levels, preoperative Japanese Orthopedic Association (JOA) score, preoperative C2-C7 lordotic angle, preoperative C2-C7 range of motion (ROM), maximal canal compromise (MCC) and maximal spinal cord compression (MSCC) were initially compared using univariate analysis. Factors with significant result in univariate analysis were included in multivariate logistic regression analysis. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) were applied to evaluate the reliability of multivariate logistic regression model. RESULTS: Univariate analysis showed that the number of spinal cord compression levels, preoperative JOA score, MCC and MSCC might be related to the presence of ISI (P <  0.05). Furthermore, multivariate logistic regression analysis revealed that the number of spinal cord compression levels (OR = 0.203, P <  0.05), preoperative JOA score (OR = 4.274, P <  0.05) and MSCC (OR = 0.250, P <  0.05) were independent preoperative risk factors associated with the presence of ISI, yielding an AUC of 0.9558. Patients with ISI showed a trend of increasing clinical symptoms and signs, and also exhibited statistically significantly increased frequencies of clumsy hands, lower limb spasticity, impairment of gait, broad-based, unstable gait, weakness and motor deficits (P <  0.05). CONCLUSION: Multilevel spinal cord compression, lower preoperative JOA score and greater MSCC are independent preoperative risk factors related to the presence of ISI on T2-weighted MRI in patients with CSM. Patients with ISI tend to have more clinical symptoms and signs, especially in lower limb manifestations and motor deficits.