Objective: To explore the clinical significance of serum midkine (MDK) levels for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the efficacy of interventional therapy. Methods: Eighty-four patients with HCC were enrolled in this retrospective study. They received an interventional treatment. A follow-up was performed every 2 months, using magnetic resonance imaging, to determine whether the treatment should be continued. Serum alpha-fetoprotein (AFP) and MDK levels were measured at the first diagnosis and during the follow-ups, and the HCC detection rates based on the cutoff values of these two measurements were compared. The relationships between AFP and MDK and the clinical tumor characteristics and changes in APK and MDK before and after treatment were also compared using a rank sum test and χ2 test, respectively. The prognostic significance of MDK for HCC was determined through regression analysis. A two-sided P