In order to evaluate the effects of cold and normothermic preservation on liver morphology, rat livers were placed in Collins' and NaCl 0.9% solutions at 4 degrees C and 25 degrees C, for 3.12 and 24 hours. Hepatocytes morphology was remarkably well conserved during cold preservation; in normothermy, only after 24 hours we noted hepatocytes swelling and karyorhexis. On the contrary, sinusoidal cells lesions were earlier (at 3 hours) and became irreversible after 12 hours of cold preservation. The signs of irreversibility (sinusoidal cells detached from the adjacent hepatocytes, pyknotic nuclei and karyolysis) were observed at an earlier stage than in normothermic conditions and during preservation in NaCl 0.9%. The mean diameter of hepatocytar nucleus and the mean hepatocytar diameter were modified, compared with the control livers, only after 24 hours of preservation in Collins' solution. Mean sinusoidal area alone was modified at 12 hours of cold preservation in Collins' solution (9.80% versus 12.10% in controls). Both histological changes and morphometric data sustained the idea that in liver preservation, sinusoidal cell lesions appeared earlier than the hepatocytes lesions. In evaluating the reversibility of the ischemic damage, attention should be focussed on the events in the sinusoidal wall.