Background: Hepatocellular carcinoma is one of the commonest cancers in world. It is one of the major health problems and its incidence is increasing. The main routinely used parameter for diagnosis of HCC is AFP, also it can be elevated in the liver cirrhosis. It represents a liver cell specific, not a tumor specific marker, for these reasons, we suggest use AFP as a supplementary marker for HCC diagnosis. So, identification of a sensitive biomarker to improve early diagnosis of HCC is in need. Aim of the work: this study was aimed to evaluate the clinical significance of serum Dickkopf-1 (DKK1) as a diagnostic and prognostic marker in hepatocellular carcinoma. Patients and Methods: in this study 100 subjects were included and divided into 3 groups, Group I: included 50 patients with HCC, and divided into 2 subgroups according to Barcelona Clinic Liver Cancer (BCLC) into early HCC (24 patients) and late HCC (18 patients). Group II: included 25 patients with liver cirrhosis. Group III: included 25 healthy subjects (control). Clinical assessment, routine laboratory evaluation, CT scan and measurements of serum alpha-fetoprotein (AFP) and DKK1 were performed to all patients and repeated to group I patients 1 month after treatment. Results: the current study showed that Serum DKK1 was significantly elevated in HCC group compared to liver cirrhosis and healthy control groups, with increased level in late than early stage. The optimum cut off values of DKK1 for diagnosis of HCC was 1.92 ng/mL (AUC 0.926, sensitivity 88% and specificity 83%). While the optimum cut off value for AFP was 102 ng/mL (AUC 0.904, 71% sensitivity and 84% specificity). Testing of both serum DKK1 and AFP increased the diagnostic accuracy for HCC (AUC 0.964, sensitivity 91%, and specificity 90%). Serum DKK1 level significantly decreases after HCC treatment with radio-frequency ablation. Conclusion: It could be concluded that Testing of both serum DKK1 and AFP significantly increased the diagnostic accuracy for HCC. Meanwhile, DKK1 can be used alone for diagnosis of HCC even in HCC with inconclusive AFP. Serum DKK1 might be a potential diagnostic and prognostic marker for HCC.