The present study was conducted to evaluate accuracy of a recently proposed method for estimating creatinine clearance (CLcr, ml/min) from actual body weight (ABW, kg), serum creatinine (Scr, μmol/l), and serum albumin (Alb, g/l) in elderly patients with muscle atrophy (the debilitated elderly). The recent method (Alb method) is CLcr=(1.6*Alb+28)*(ABW/Scr) for males and CLcr=(1.1*Alb+25)*(ABW/Scr) for females. In 46 debilitated elderly inpatients (64-96 years of age), CLcr was actually measured, and it was estimated by Cockcroft and Gault's method (C-G method), the C-G method corrected by lean body weight (LBW method), and the Alb method. The accuracy was accessed by mean prediction error (ME, ml/min) and mean squared error (MSE, [ml/min] 2 ). The C-G method yielded ME=7.39 and MSE=448.3, the LBW method gave ME=6.33 and MSE=385.9, and the Alb method provided ME=3.66 and MSE=196.1. The Alb method was found the most accurate in the debilitated elderly.