Weanling male rats fed on a hypolipotropic diet develop acute renal failure whose morphological features vary from focal tubular necrosis to cortical necrosis. We have sequentially studied the hemostatic mechanism in correlation with the morphology of various tissues, mainly renal and hepatic, in choline-deficient rats as well as in three control groups. No important changes were observed in the hemostatic mechanisms before the development of tubular necrosis. Along with tubular necrosis a consumption coagulopathy was found, evidenced mainly by a decrease in the activity of factors V and VIII as well as a prolongation in PTTK and Quick’s time and a decrease in platelets. Fibrin degradation products were found in serum and urine and soluble fibrin monomer complexes in the former. Following tubular necrosis thrombi were found in the renal microvasculature. It is possible to speculate that the tubular necrosis induced by choline deficiency could produce an activation of the coagulation system which in turn would lead to thrombosis of the renal microcirculation and cortical necrosi