The electrochemical behavior ofd-penicillamine (d-PA) studied at the surface of ferrocene carboxylic acid modified carbon paste electrode (FCAMCPE) in aqueous media using cyclic voltammetry and double step potential chronoamperometry. It has been found that under optimum condition (pH 7.00), the oxidation ofd-PA at surface of such an electrode is occurred about 420 mV less positive than that an unmodified carbon paste electrode (CPE). The catalytic oxidation peak current was linearly dependent on thed-PA concentration and a linear calibration curve was obtained in the ranges 7.5×10-5 M – 1.0×10-3 M and 6.5×10-6 M-1.0×10-4 Mofd-PA with cyclic voltammetry(CV) and differential pulse voltammetry (DPV) methods respectively. The detection limits (3s) were determined as 6.04×10-5 M and 6.15×10-6 M. This method was also used for the determination ofd-PA in pharmaceutical preparation (capsules) by standard addition method.