Variations in DNA synthesis (DNAs) and Nucleolar Organizer Regions (NORs) were studied in the littoral cell population from regenerating liver of C3HS inbred mice standardized for periodicity analysis. Immunohistochemical detection of Bromodeoxyuridine (BrdU) with a monoclonal antibody and silver staining of NORs (AgNORs) were assessed by means of a digital image analysis system in histological sections. Tissue samples were obtained every four hours from the 30th to the 54th hours after a partial hepatectomy. The results showed, in both parameters, a gradual increment of the values during the period studied, with highest values (DNAs 107.1 +/- 16.1 SE; AgNORs 77.3 +/- 3.4 SE) located at 16:00/54 Time of Day / Hours Post-Hepatectomy (TD/HPH), which were significantly different (p <0.001) from the values of the first sample (DNAs 38.1 +/- 9.5 SE; AgNORs 27.3 +/- 1.0 SE) taken at 16:00/30 TD/HPH. The results of our experiment demonstrate the existence of a strong correlation of DNA synthesis measured by BrdU immunohistochemistry and AgNORs numbers in sinusoid littoral cells from mouse regenerating liver.