Hepatocellular carcinoma (HCC) is one of the most frequent primary malignancies in the world, and, particularly, it is common in the Far East. In the world, more than one million new cases of HCC are seen each year. The prognosis of patients with HCC is extremely poor with an average survival of about six months following the diagnosis. In order to improve the prognosis of HCC, early diagnosis should be attempted utilizing mass screening methods. Screening of a high-risk population with alpha-fetoprotein (AFP) along with non-invasive medical imaging modalities will lead to early diagnosis of HCC and subsequent improvement of survival. Indeed, recent advances in medical imaging techniques have increased the rate of detection of small HCCs, and such imaging modalities include ultrasonography(US), radionuclide imaging(RNI), computed tomography(CT), magnetic resonance imaging(MRI), and angiography. Each imaging method is reviewed with special emphasis on the early diagnosis of HCC.