Hepatocellular carcinoma (HCC) is one of the most life-threatening cancers. The present study was designed to chronologically analyze the HCC chemically induced by diethylnitrosamine (DEN) in male Wistar rats during a 27-week period. DEN was given to rats in drinking water (100 mg/L) to induce HCC. In the present study, the DEN-administered groups recorded dramatic results in the tumor markers, oxidative stress, lipid profile, liver function, and hematological parameters at all intervals when compared with their corresponding values in the control groups. In addition, the morphometric analysis of livers of the DEN-administered groups (from 9 to 27 weeks) showed gradual enlargement and several grayish white nodules and foci on the peripheral surface of the liver as the features of HCC. In conclusion, the present sequential model chronologically analyzes all steps of hepatocarcinogenesis and presents a new staging system for classification of HCC that may be valuable for investigating the effects of anticarcinogenic compounds at varying stages of hepatocarcinogenesis in vivo.