It has been reported that the pharmacokinetic behaviors of drugs which are mostly metabolized in the liver are significantly different in patients with renal failure. Theophylline(TP) is mainly metabolized in the liver (approximately 90%) and renal clearance of the drug is negligible (less than 10%). Therefore, we have investigated the changes in pharmacokinetics of theophylline in normal, G-ARF and U-ARF rats after an intravenous administration. The total body clearance of TP decreased approximately 40% in U-ARF rats. The reduced CL$_{T}$, value in U-ARF rats could be due to reduced hepatic intrinsic clearance by up to 40% since it has been published that plasma protein binding of TP and liver blood flow does not change in U-ARF rats.