We examined the effect of dietary conjugated linoleic acid (CLA) on liver regeneration after a partial hepatectomy (PH) in Sprague-Dawley rats. PH was performed on rats fed a 0 or 1 wt.% CLA diet for 3 wk. Average liver weight in the CLA fed rat population was heavier than the control rat population at the time of PH and 1-d after PH. Conversely. CLA fed rats' liver weight was significantly lower than control rats at 7-d after PH. This suggests that dietary CLA reduced liver weight gain after PH. Dietary CLA did not affect serum aspartate aminotransferase (AST) or alanine aminotransferase (ALT) activities. However. CLA significantly reduced serum albumin levels at 1-d but not at 7-d after PH. 5-Bromo- and 5-iododeoxyuridine incorporation into hepatocytes 1-d post PH was lower in the CLA group. In conclusion, the data suggests that dietary CLA inhibits DNA synthesis after PH, which results in hepatocyte proliferation inhibition.