Studies were aimed to analyse CT images and time-density curve (TDC) reconstructed from the serial CT imagesin experimentally induced acute renal failure (ARF) of the rabbits using dynamic CT, and to try to evaluate in thefunctional aspect, and finally to promote the better understanding of pathophysiology of ARF. All 32 rabbits were divided into four groups. Group I (6 rabbits) was the control. Group II (7 rabbits) was the nephrotoxic ARF at 24 hours after HgCl2 injection. Group III(15 rabbits) was the nephrotoxic ARF at 48 hours after HgCl2 injection. Andgroup IV ( 4 rabbits) was the ischemic ARF at 24 hours after renal cortex and medulla on the sequential CT images. and compared in the functional aspect. Nephrotoxic ARF was induced by an intravenous injection of HgCl2(3mb/kg) and ischemic ARF was produced by a temporary ligation of left renal artery for 2 hours. The results were as follows: 1. On the sequential CT image, the cortical and the medullary densities of group I were rapidly increased and decreased. The cortical densities of group II and III increased rapidly and then decreased more rapidly thangroup IV were lower than those of group I. 2. In the TDCs of group I, the densities of aorta, cortex and medulla increased sequentially to form peaks and then declined rapidly in order. 3. The cortical curves of group II andIII were increased to form high peaks and decreased rapidly. The medullary curves were low and flat. 4. In groupIV, both cortex and medulla showed lower curves than those in group I. The medullary curve revealed a slightly upward slope. 5. Between the curves of aorta and cortex, and the curves of cortex and medulla in ARF groups, junction times were delayed or the curves did not intersect apparently. These studies were able to demonstarate meaningful differences in both the dynamic CT images and the functional curves of the conntrol and two experimantal ARF models.